I have seen these command rejected earlier too while sending from Mail box. One of our clients where we get such answers from, admin told us, SERP sends incorrect email headers.
I've found an issue which I'm trying to find the best way to resolve.
An integrated proof of delivery system sends two pieces of data to the SERP API, in two separate calls - let's c...
There are some topics in this Q&A related to this question, but none of them is about Idle users - Concurrent or Named.
If timeout minutes are specified in Optional Features, then all idle users are...