Taken to app store instead of the meeting.

[MarcusHBailie]

When I try to join a meeting on my MacBook Air,  I'm taken to App Store instead of the meeting.  Why is this and how do I stop it? I have uninstalled zoom.us then re-installed it.  Rebooted etc.  All the usual stuff.  This doesn't happen on my Mac Desktop.  What's going on?