Start by disabling all of the options in the .htaccess Maker and create the .htaccess file. Then start enabling options one by one. This will allow you to see which option throws a 500 error. If you spot one which has several sub-options (like the front-end or back-end protection) simply try reverting the changes you made to those options. If you spot the problematic option but you are not sure how to work around it, post here and I can help you from there.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!