Plugin activation loading forever

so i installed my elgg websites (elgg 2.3.3) and copied some plugins like email handler, or friend request. I logged in and go to plugins and try to activate them, but it always show loading (that circle loading on top) 

i wait about 30 minutes and same. I already put the plugin on top or on bottom, but still the same. it always show loading circle. the plugin is compatible and no conflicts. it is same on few plugins, cannot activate

can anybody help me? i am new to this

thank you