Please check the followings.
- Make sure that the transmitter and receiver are using the same channel. The following article guides through this:
https://www.roland.com/us/support/knowledge_base/4412341626139/ - Note that the WL-30XLR is compatible with dynamic microphones and is not compatible with condenser microphones.
- Check whether the volume is up on the amp or mixer. One way of testing this is to connect the microphone directly to the amp or mixer and check is sound is heard.
- Move the receiver and transmitter closer together, if they are far apart.
- Objects between the receiver and transmitter may cause an unstable connection.