Not Acceptable

I haven’t seen that error before, but this seems to imply it’s an htaccess issue:

https://www.ads-software.com/support/topic/an-appropriate-representation-of-the-requested-resource-wp-adminoptionsphp?replies=10

One of my favorite it-works-but-don’t-ask-why fixes is to go into your Permalinks settings and simply hit Save. Don’t change anything, just hit Save. More often than not, it fixes weird WordPress problems.

Good luck!

–David

I have the same problem also disabling the permalink, and on 2 different websites hosted on fastcomet:
https://www.spesagodina.it/libroingredienti/
https://www.spesagodina.it/web/

You shouldn’t disable the permalink, just resave permalinks.

But after that, it’s likely a hosting-related issue.

–David

I resaved the permalinks, but I stil receive the same error, my hosting is fastcomet.com and I was never having troubles with permalinks..