Admin -Changing Theme (Content-Design-Configuration) Help Need

[Rocket3167]

When I select the theme ex. default -Action(Edit) and then select from the dropdown -Applied Theme and hit Save Configuration page acts like it's saving but I receive a 404 Page not found? Can someone help me figure this out? I've tried with a fresh installs using 2.1.7 and 2.1.8 and both giving me the same results.

Within my browser bar I get: www.domain.com/admin_*******/theme/design_config/save/key/4752cd83f3be3e6d709647c6b2446bdae7f16d6c48...

404 Page Not Found

Upon initial setup Ive ran:

php bin/magento indexer:reindex

php bin/magento setup:upgrade

php bin/magento cache:flush

php bin/magento setup:di:compile

My cache management has been disabled. Any and all help would be appreciated!

Brian

[Rocket3167]

Anyone have any ideas? Cant believe that no one has had this issue. I can't change my theme or logo as every time I hit the SAVE Configuration it reloads the page displaying 404 error: Page Not Found. Been stuck on this for over a week and cant find any solutions.

[Rocket3167 · Accepted solution]

Solved 

I was able to find the solution and it was mod_security. I edited my modsecurity.conf file

From: SecRuleEngine On

To: SecRuleEngine Off

Hope it helps if some else has the same issue!

[sethzweig]

This solved my issue - the reason it bombs out is you must have some javascript calls in your header/footer inputs for the page - this gets flagged by modsecurity