So recently we had this error pop up on our website, we believe we have narrowed it down to a theme problem. Has anyone else had this issue? If so how did you resolve it?
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘arphabet_widgets_init’ not found or invalid function name in /home/serveit8/public_html/clients/z-clients/livingfaith/wp-includes/class-wp-hook.php on line 286
We have deactivated all plugins and restored older theme backups to no avail.
deactivate all third party plugins and try again your problem, most probably this I conflict with third-party plugins.
Once you deactivate all plugins please check your problem again, if the problem is gone then this means it was a plugin conflict. Now, start activating plugins one by one and same time repeat your problem until your problem appears again, now you know which plugin was in conflict
update everything - plugins, theme, WordPress and check again
switch to default wp theme and check again if you see the same problem