500 Internal server error

I’ve gone through various changes including an upgrasde to Mautic 2.14 and now I can’t get anything to connect.

If I use OAuth1 then I get a blank window in WP

If I use Oauth2 then, after logging in, etc. I get an Error 500, INternal SErver ERror”

I’ve tried on both our production Mautic and our mautic.com account

It seems the plugin is thoroughly broken

Any hope?