Nikolai,

Thanks for your reply. I watched the video. But sorry to say that it doesn't solve my problem. I download the latest version and install it properly, without an error. But adding user causes problem that I told in the previous messages.

When I check my server only database server a bit different than yours

I don't think that that cause the problem. 

I didn't write that my video solves your problem. The video only proves that the problem isn't in Elgg core but in your server.

You need to dig deeper to find the cause.

This can be done, for example:

1 - Logs

Try to expand the log report on the errors because your report doesn't do anything.

Activate the bundled 'Developer Tools' plugin and enable error log

You can enable/set more options there to collect of all types of logs.

Also set Log level option on 'Log everything' in the site settings.

You may need to look at the log configuration for your server, PHP and MySQL.

Now clean all logs, try to register on your site, or add new user and immediately look at logs.

2 - Trace logs via action/form

You can check which parameters are passed and/or which ones don't work to see at what step this happens.

If you're a developer you can do this with this elgg_log() function.

Just log what you get and what gives you an error.

You can do it in the register action/form files.

Nikolai,

Thanks for interest and patient. I am new on using elgg. So I am  knowledgable on Elgg. I did what you said and activated the plugin. Then I tried to add a user on welcoming page. then logged in as admin. Finally I found what cause the error. But I don't know what to do to overcome the problem. I summed the error log belowbecause Its very long.

----

Exception at time 1663081605:

Laminas\Mail\Transport\Exception\RuntimeException: Unable to send mail: Unknown error in /***/****/****/usumda.com/public_html/vendor/laminas/laminas-mail/src/Transport/Sendmail.php:298

Stack trace:

#0 /***/****/****/usumda.com/public_html/vendor/laminas/laminas-mail/src/Transport/Sendmail.php(130): Laminas\Mail\Transport\Sendmail->mailHandler()

#1 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/EmailService.php(183): Laminas\Mail\Transport\Sendmail->send()

#2 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/EmailService.php(119): Elgg\EmailService->transport()

#3 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/SendEmailHandler.php(48): Elgg\EmailService->send()

#4 [internal function]: Elgg\Notifications\SendEmailHandler->__invoke()

#5 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/HandlersService.php(63): call_user_func()

#6 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/PluginHooksService.php(69): Elgg\HandlersService->call()

#7 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationEventHandler.php(288): Elgg\PluginHooksService->trigger()

#8 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationEventHandler.php(270): Elgg\Notifications\NotificationEventHandler->deliverNotification()

#9 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationEventHandler.php(198): Elgg\Notifications\NotificationEventHandler->sendNotification()

#10 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationEventHandler.php(56): Elgg\Notifications\NotificationEventHandler->sendNotifications()

#11 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationsService.php(346): Elgg\Notifications\NotificationEventHandler->send()

#12 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/lib/notification.php(224): Elgg\Notifications\NotificationsService->sendInstantNotifications()

#13 /***/****/****/usumda.com/public_html/mod/uservalidationbyemail/lib/functions.php(58): notify_user()

#14 /***/****/****/usumda.com/public_html/mod/uservalidationbyemail/classes/Elgg/UserValidationByEmail/User.php(58): uservalidationbyemail_request_validation()

#15 [internal function]: Elgg\UserValidationByEmail\User::Elgg\UserValidationByEmail\{closure}()

#16 /***/****/****/usumda.com/public_html/vendor/php-di/invoker/src/Invoker.php(74): call_user_func_array()

#17 /***/****/****/usumda.com/public_html/vendor/php-di/php-di/src/Container.php(279): Invoker\Invoker->call()

#18 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Invoker.php(96): DI\Container->call()

#19 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/lib/elgglib.php(593): Elgg\Invoker->call()

#20 /***/****/****/usumda.com/public_html/mod/uservalidationbyemail/classes/Elgg/UserValidationByEmail/User.php(59): elgg_call()

#21 [internal function]: Elgg\UserValidationByEmail\User::disableUserOnRegistration()

#22 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/HandlersService.php(63): call_user_func()

#23 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/PluginHooksService.php(69): Elgg\HandlersService->call()

#24 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/lib/elgglib.php(381): Elgg\PluginHooksService->trigger()

#25 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/actions/register.php(57): elgg_trigger_plugin_hook()

#26 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Router.php(274): include('/home/u72955929...')

#27 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Router.php(209): Elgg\Router->getResponseFromFile()

#28 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Router.php(121): Elgg\Router->prepareResponse()

#29 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Router.php(101): Elgg\Router->getResponse()

#30 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Application.php(454): Elgg\Router->route()

#31 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Application.php(345): Elgg\Application->run()

#32 /***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Application.php(395): Elgg\Application::route()

#33 /***/****/****/usumda.com/public_html/index.php(8): Elgg\Application::index()

#34 {main}

----
Exception :
{

    "class": "Laminas\\Mail\\Transport\\Exception\\RuntimeException",

    "message": "Unable to send mail: Unknown error",

    "code": 0,

    "file": "/***/****/****/usumda.com/public_html/vendor/laminas/laminas-mail/src/Transport/Sendmail.php:298",

    "trace": [

        "/***/****/****/usumda.com/public_html/vendor/laminas/laminas-mail/src/Transport/Sendmail.php:130",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/EmailService.php:183",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/EmailService.php:119",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/SendEmailHandler.php:48",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/HandlersService.php:63",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/PluginHooksService.php:69",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationEventHandler.php:288",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationEventHandler.php:270",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationEventHandler.php:198",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationEventHandler.php:56",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Notifications/NotificationsService.php:346",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/lib/notification.php:224",

        "/***/****/****/usumda.com/public_html/mod/uservalidationbyemail/lib/functions.php:58",

        "/***/****/****/usumda.com/public_html/mod/uservalidationbyemail/classes/Elgg/UserValidationByEmail/User.php:58",

        "/***/****/****/usumda.com/public_html/vendor/php-di/invoker/src/Invoker.php:74",

        "/***/****/****/usumda.com/public_html/vendor/php-di/php-di/src/Container.php:279",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Invoker.php:96",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/lib/elgglib.php:593",

        "/***/****/****/usumda.com/public_html/mod/uservalidationbyemail/classes/Elgg/UserValidationByEmail/User.php:59",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/HandlersService.php:63",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/PluginHooksService.php:69",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/lib/elgglib.php:381",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/actions/register.php:57",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Router.php:274",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Router.php:209",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Router.php:121",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Router.php:101",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Application.php:454",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Application.php:345",

        "/***/****/****/usumda.com/public_html/vendor/elgg/elgg/engine/classes/Elgg/Application.php:395",

        "/***/****/****/usumda.com/public_html/index.php:8"

    ]

}

---

I am looking forward to hearing of you soon.

Uservalidationbyemail plugin is a reason. Correctly, the cause of issue is that your server cannot send emails.

But deactivating this plugin (and turn off all options to validate new users by email) is solved this problem.

True, you've a new problem now: setting up a mail server ))
Search on Community, there have been discussions.

Nikolai,

Thanks again. Now one can register himself without any error. 

That's very kind of you to help me on this issue. 

I will search on setting up a mail server.

Nikolai,

I am lost in discussions to set up a mail server for my elgg. 
I want to get users register themselves to my website after being validated by me. I tried to find something through the discussions, as you adviced, but maybe my english or my inability of coding  made my mind blocked by many many discussions.

I read about a plugin that is mailgun, but it looks its version is not supported by elgg 4.x. It warns me This plugin has't been updated in over 6 years. It may no longer be maintained.

One of assistants in my hosting server, hostinger, advices me to Send emails by using PHP script (php Mailer). As far as I see this means to write a code. Does it mean to create a php file somewhere in elgg? or edit a file in Elgg?

I need your help.

All in the elgg-config/settings.php + CRON:

https://www.php.net/manual/en/mail.configuration.php

http://learn.elgg.org/en/stable/appendix/faqs.html#missing-email

https://elgg.org/discussion/view/3077430/configuring-smtp-settings

https://elgg.org/search?q=smtp+email&entity_type=object&entity_subtype=discussion&offset=0&search_type=entities

Nikolai,

At last, I managed to arrange the smtp settings with your help. Thanks a lot. Now user validation by email plugin runs properly. It sends validating emails successfully. Your assists are invaluable for me. Thanks again.

I'm glad I could help you