I am an old (71 y) software developer from Germany, specialized in Microsoft technologies C#, ASP, MVC. I also develop plugins for SmartStore - an online store. Was CEO of a GmbH for a long time. In retirement age I moved to Bulgaria to live, but I still work and operate Internet sites based on SmartStore for customers. In Bulgaria I also run a company. My Internet sites run on virtual servers under MS IIS. At the moment I have massive problems with the certificates from Let's Encrypt. I was not able to activate them neither for the internet pages nor for the mail servers. I have tried the mail servers Mail Enable and Axigen.