Problems With Blue Yeti Mic & MacBook Pro

I've just purchased a Blue Yeti Mic for a podcast. For the podcast, I will be using my MacBook Pro and Zoom.

However, there are two issues:

1) As soon as I plug the mic into the MacBook (via a small adapter), the sound level (on the MacBook) goes down gradually (the volume symbol appears in the middle of the screen), and there is no way to bring it back up. Nothing is muted. The only way to sort the issue is to unplug the mic a few times, then it eventually resolves. Obviously, this isn't ideal.

2) Today, I tried two different Zoom calls with different people. As soon as I plugged in the Yeti mic, I couldn't hear the other person. Both people were on different products (one was on a laptop, one was on a phone) and the Zoom chats were totally separate. I changed all the settings in the volume settings (outputs, inputs) but I couldn't hear them no matter what I did.

What am I doing wrong?