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Hello ethem56,

I would suggest you installing Health Checkup Plugin.

https://wordpress.org/plugins/health-check/

It will perform a number of checks on your WordPress install to detect common configuration errors and known issues.

Try the Troubleshooting Mode in the plugin, and see if you are able to perform normal actions then, if you can, it would appear the issues are introduced by your theme or one of your plugins.

Thanks,
Kartik

May be a plugin or theme conflict. Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.

Sorry ethem56, that the solution suggested didn’t work.

I would recommend taking help from some expert on this or wait for some-else to respond if someone has faced a similar issue and have some solution.

Thanks.