Critical Error

The reason for the error should be visible in the error log. You can find it in your hosting area. If necessary, the support of your hosting can help you.

Alternatively, you could also enable debugging in WordPress. How to do this is described here: https://www.ads-software.com/support/article/debugging-in-wordpress/ – also here the support of your hosting can help you if necessary to edit the file accordingly.

In both cases you should be able to see what the cause is in the logfile.

The fastest way to debug this is to Deactivate all plugin one by one and see if you can create posts . So Deactivate one Plugin and try to create a post, see if it works. If this does not help, deactivate another one and so on.

If Deactivating Plugin does not help, Activate a Default WordPress Theme and check again.

Finally, if you still have the issue, you can use any File Manager plugin and check your error_log in your Root folder. The file should look like this: https://imgur.com/a/UuvWpgs

Let me know how it goes. Thanks

@moinrrahmed: A file error_log only exists for very few hostings on this position. If you can’t find any error log, you should ask the hoster’s support team, as I described above.

@threadi Yes, you are correct. I suggested File manager plugin because it is the fastest way to find if there is any error_log file available in the Root folder else he can contact the Hosting support.