The single most useful thing you can give us is when it happened. Our engineers find the cause by looking at server activity around that moment — a timestamp turns a guess into a five-minute fix.
Always helpful
Roughly what time it happened (even "about 10 minutes ago" works)
A screenshot of the error — the whole window, not a crop
What you were trying to do in plain words
The order, job, or item you were working on
Not needed
Don't try to diagnose it for us, and don't retype error text — a screenshot is better than a transcription. If you were mid-way through something, tell us where you got to and whether you've tried again since.
If you're chatting from inside the tool
Most of this is captured automatically. Just describe what went wrong.