When that happens, there is either:
- a mismatch of multiple accounts (between the one CA was connected to when it created the Zoom meeting and whichever one you're logged into in the moment),
- OR a matter of the Zoom desktop client botching that matching to properly recognizing you (as logged in via the desktop app) as the one connected to that account under which CA created that Zoom meeting.
Case 1 is simple to fix: make sure you're logged in to whichever Zoom account the Zoom meeting was originally created under.
Case 2 is maddening, though does seem to be happening as of a recent (early 2023) update to the Zoom desktop client. People who have (and have ever had) only a single Zoom account have encountered this problem.
When it occurs, the remedy is as simple as logging in to your one account newly on zoom.us, and then try joining again. This ensures that your desktop Zoom client actually recognizes you as ye, the proper host of the meeting. (That this works suggests it's truly a Zoom issue, sigh).