Defender or Hummingbird Conflict with WordFence or JetPack/WP Authentication

Yesterday I have applied some of Defender's recommeded settings and website seemed OK. I have also used Hummingbirds script allocation/moving function to try to improve load time. I believe I moved JetPack scripts as part of it. Yesterday everything seemed ok, but today when session expired, I cannot login into the website any more. Neither Wordfence login with text message authentication nor WP (JetPack) login are not working. It hangs for a while and then throws the 500 error Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator and inform them of the time the error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.

Apache Server at riverdentistry.com Port 80.

How do I revert/undo changes or disable plugins to be able to login?
my contact info is 806-470-7584 or michael@ogisolutions.com..

Thank you,

Michael