hi pankaj!! thanks for answering!
the issue mentioned in the first post is related to the frontend...
I'm trying to login now but I'm getting this error: Warning
The security token did not match. The request was aborted to prevent any security breach. Please try again.
I tried with different users... I even tried with the user assigned to joomlart... also in firefox and chrome... but nope... couldn't login...
ADDED: in the meanwhile, I had to disable T4 plugin again and assign cassiopeia to all pages because was the only way to login back in the frontend...
please, do you know what would it be?
thanks!