Hi @wangzy,
Could you review this web page and send us the relevant logs, config files, etc. so we can diagnose this issue?
Additional details that might be helpful:
- What distribution and database is your Mattermost instance installed on?
- Which browser/desktop app (and version) are the two users using? How about operating system?
- Does the issue reproduce with more than one person?
- Does the issue reproduce each time, if you try to call the same person 2-3 times? (sometimes we’ve had issues in the past where first try doesn’t connect)
Can you also help take a look at the tips in these threads: