Hard to trouble shoot without details or being there.
Try the LINE in instead of MIC in. What scanner are you using? It is best to use RECORD out if your scanner has it.
If you only have a MIC Input:
Open the mixer software on your computer
Go to Recording properties
Look in Advanced Settings for a check box labeled "Microphone boost" or "20dB boost" or similar
Make sure that the boost check box is cleared since you do not want to amplify the strong audio from the scanner any more than it already is!
Have you actually connected to RR and sending audio? Is the "static" heard from listening to the feed, your computer, your scanner?
Make sure nothing else is using the same port.
Have you read Setting up your Broadcasting Station