Some windows system users couldn't join in the meeting room

Hi. 

Please make sure their windows application is up to date, and that the software is up to date.

If updating Zoom doesn't help :

If they are typing the passcode, try having them copy and paste it in instead - from a know good source - like an invitation email.

If that have to type it in manually, go through the usual steps of making sure they do not have caps lock on, num-lock confusion, and they are not transposing things like 0 and O and I and l. 

You can also have them open a notepad in windows and type down the passcode as they are entering it. That will show them/you whether every keypress is generating the right character. 

A common problem I experience with users at my company is that people don't realize passcodes are case-sensitive.  For instance, lots of people have "covid" as a passcode.  Yet people try to join by typing "COVID", which doesn't work because it's supposed to be lowercase.  Because of this, I advise against using letters in one's passcode.

It's also best to share the passcode-embedded link with people.  When people click on this link, then they don't even have to enter the passcode, so it removes the chance of people entering the passcode incorrectly.

Also, it's not very difficult to accidentally change one's passcode.  I would double-check the passcode in both the invite that was sent out and in your Zoom application.  You can check on it in Zoom by hitting Schedule from the home screen (or by going to Meetings and then hitting Edit under the Meeting ID you're using), then check the Passcode field to make sure it's still the one you want.

I noticed especially that people who use the Zoom Outlook plugin seem to have their passcodes mysteriously change, so I think the Outlook plugin tends to mess things up--I'd advise scheduling through the Zoom application instead of through the Outlook plugin.