On a number of websites I have gone into Configure WAF and set "Change admin URL' to a value e.g. banana, so the new admin URL would be https://mywebsite.com/banana
This works fine initially but at some point it stops working and you just see the message "Access forbidden, please contact support". Sometimes I can fix this by deleting .htaccess and regenerating using the .htaccess Maker. This does not work on all occasions though and even going back into WAF to set "Change admin URL' back to null does not revert to the standard wp-admin login URL.
Why is this happening and how do I resolve this?