May be i missed something in the translation, so sorry if that is the case because i might not understand this clearly
DDaher werde ich das Programm auf den Stand Anfang des Jahres zurücksetzen und testen ob damit die E-Mails vom Server versandt werden können.
Translated
Code:
Therefore, I will reset the program to the status at the beginning of the year and test whether the emails can be sent from the server.
DO NOT delete your application or any files, also don't replace any, just rename them, so if the problem was/is in the permission you will need them to get to the bottom of this problem and understand this in clear way, in case the problem is attached to them, then they worth money and time for you (to analyze).
Just rename all the files you want to replace and keep them on the server for future references.
Try with the same folder(s) or rename the folder in full too, also don't delete them until you are 100% they are irrelevant.