First go to Admin Tools, Web Application Firewall, Configure WAF. Make sure "Log blocked requests" is set to Yes; if it's not, set it to Yes and click on Save. Now try reproducing your issue. Immediately after that, please go to Admin Tools, Web Application Firewall, Blocked Requests Log. The latest log entry at the top should have the date and time of when the issue occurred. Please copy the Reason and Target URL here so that we can further help you.
If, however, you do not see a log entry, or the Date and/or IP address do not match your last access, this problem is not caused by Admin Tools' WAF. In this case, you will have to do some .htaccess troubleshooting. You may need to read the general .htaccess troubleshooting page, as well as the page on finding out necessary .htaccess exceptions.
Nicholas K. Dionysopoulos
Lead Developer and Director
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