Sonarr saying port is in use, but it's not?

Troubleshooting
6

I got it working in the end,

I looked at the file /mnt/dietpi_userdata/sonarr/config.xml

<Config>
  <LogLevel>info</LogLevel>
  <UrlBase></UrlBase>
  <UpdateMechanism>BuiltIn</UpdateMechanism>
  <AuthenticationMethod>None</AuthenticationMethod>
  <ApiKey>2329d0fc000741f48fc39cb7a6347593</ApiKey>
  <Branch>master</Branch>
  <BindAddress>*</BindAddress>
  <Port>7878</Port>
  <SslPort>9898</SslPort>
  <EnableSsl>False</EnableSsl>
  <LaunchBrowser>True</LaunchBrowser>
  <SslCertPath></SslCertPath>
  <SslCertPassword></SslCertPassword>

Changed the port to 8989
restarted sonarr, and all is good.

Again this was a fresh install, and I never touched this file.