I looked into the issue and it seems like this is a hosting problem most likely to do with mod_security. Please contact your webhost for this. I’m trying to see if i can revamp the settings page so it does not trigger this error.
You can use the following mail template (including screenshot attached). In
Dear Sir/Madam,
Recently, I’ve been experiencing a problem whilst using a WordPress installation. It has come to my understanding that it is most likely a mod_security issue. Upon saving the setting page for this plugin i get the following error:
Not Acceptable
An appropriate representation of the requested resource /wp-admin/options-general.php could not be found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Please see the attached screenshot for the request on which it occurs.
https://screencast.com/t/PujwlGJqnk
Best regards,
Friso