Thanks for this thread. After 2 weeks of self-diagnosis and repair attempts, an email and a phone call with Strato, with reference to this thread, the error was fixed by Strato.
"By the time you sent us your email, there was limited functionality in some virtual servers as a result of software updates.
However, our data center has resolved these limitations. So you should not receive the error message anymore."
"By the time you sent us your email, there was limited functionality in some virtual servers as a result of software updates.
However, our data center has resolved these limitations. So you should not receive the error message anymore."