Singleton in plugin fails on AJAX call (Plugin initialzed again)

So I think I found a sorth of solution. I just check each new request of the request wants to acces wp-json, if so load the ajax based on the url otherwise initialize the plugin. Seems to work so far.

Thanks for the replys guys!

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)