Execution of failed & sync errors

I have searched the forum but was not necessarily able to find a useful fix for the “Execution of failed error & sync” issues even though I tried all offered remedies. 

Could anyone know a stable answer for the following errors? If yes, it’d be highly appreciated!

Thanks in advance.


The client also and constantly gives the error in the last screen shot and it is not “temporary!” All settings are smoothly set.