Login Not Acceptable

“Not Acceptable” is not a normal WP error.

Make sure that is the EXACT error you’re getting and, if so, turn off any WordPress login protection plugins.

I have been getting this same thing, on sites that I manage that all happen to be on the same web host.

I think they have updated some security which has caused me some issues.

Anyway, what I needed to do was upload a .htaccess file to the wp-admin folder of the site (you can do this via FTP) with only the following in it:

<IfModule mod_security.c>
 SecFilterEngine Off
 SecFilterScanPOST Off
</IfModule>

Try that, see how you go

Might be Better WP Security
I can’t turn off since I can’t get in. Until I get in. And it’s random so I can’t say if it’s fixed or not.

I find that going to the networkurl/wp-admin works even when other
site/wp-admin fails.

If you can get to there, can’t you then get to My Sites > Network Admin > Dashboard > Plugins and network disable it from there?

Did you try my other suggestion? It has always worked for me when faced this with this issue (which I have only faced in the last month or so, without having added any new plugins)

Hi I have the same problem, tried the .htaccess file but problem the same.
Using Better WP Security and recently updated it !

Mark

Hi Mark

After updating Better WP Security, is that when the problem started?

If you have FTP access to your site you can disable this plugin by renaming that particular folder, and then see if you can access your site

The one workaround I’ve found, is login using the /network/ URL
that seems to work fine
Or else it’s clearing the browser cache.