External microphone not detected on Red Hat Enterprise Linux Workstation 7.9

i'm using BY-MM1 Boya Mic on my Linux computer. I'm trying to record the screen using the Blue recorder. However, after recording, I can only see the video but the audio is very weak. It means my Linux system does not detect the external mic.

I'm using Red hat Enterprise Linux workstation 7.9. how to solve this problem? Please help.