Hello,
let's be sure this is caused by Admin Tools.
First of all replace your current we.config with Joomla default one and disable Admin Tools - System plugin.
Your link works?
If it still doesn't work, it means that the problem is somewhere else and not in our software.
However, if you can login, please try to enable the system plugin again. You should be blocked and a security exception should be raised. Get inside Admin Tools component and in the Security Exceptions log please take a look at the blocking reason and post it here; I'll help you to work around your issue.
Davide Tampellini
Developer and Support Staff
🇮🇹Italian: native 🇬🇧English: good • 🕐 My time zone is Europe / Rome (UTC +1)
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!