Hi,

i have had a similar problem when upgrading from version 5 to 6.

In my case, this was due to the specifying Javascripts in Config.pm.

After removing those settings from the Config.pm, logins worked again.

I've written a blog post on upgrading, maybe there is some useful info

in there for you.

https://www.ictforce.be/2017/otrs-upgrade-5-to-6/

Regards,

Benedict