It seems owncloud does not accept ampersands (&) in their passwords. I had tried resetting my password using the softaculous ‘Edit Installation’ feature but it didn’t work initially, until I removed the ampersand from my password. I was then able to login. It would be good to let softaculous know about this, or have this somewhere in the documentation (If it’s not there already)
created a user “test2” with a password “test&test”
logged out with the admin user
logged in with the new test2 user and the password using an ampersand
see that a successful login with that password having an ampersand was possible
Maybe this is a problem with Softaculous only? e.g. there could be some mishandling in the ampersand for the used web server configuration?
In this case i don’t think that any of the ownCloud people has any contact with Softaculous and i think you could open a bug report with the Softaculous support.