Then, try to activate the plugin again. If it still doesn't work, switch to a default theme temporarily, disable all non-WPML plugins and see if you can get activated.
Did you switch to a default theme and activated String Translation? Did that work?
I tried to login with the details you provided but those no longer seem to be working. I would login details to take a look at your site and permission to enable/disable themes, plugins. Please let me know if that's okay or not.
Hi Raj, thanks for following up. I just tried update my theme and it seems working now. If you wanna check the backend of the website please use the same username and password: 123456
Thanks!