So you just detach the mic and put it into the jack right?
Do you have discord and zoom active at the same time? There is a restriction, that you can only use one application and one hardware mic input at the same time. It is bound for the active program and cannot be used for any other program during this time.
Here is an example how you could loop or remap the mic or speaker so that you can use them on different applications at the same time:
