You can use any station in TuneIn/My Radio Stations in an alarm. Where exactly is “AccuRadio” in your Sonos configuration?

I find it under My Sonos/Stations or if I tap Browse, AccuRadio is one of the listed radio stations like TuneIn.

Oh its an actual Music Service. You need to ask AccuRadio to mark their content as usable as an alarm. See isEphemeral on https://developer.sonos.com/reference/types/smapi-object-types/#streamMetadata :

• True if the stream is short-lived. If so, Sonos players will not allow it to be added to Sonos Favorites or alarms. False if it is not short-lived.

AccuRadio also need to declare their entire service as alarm-able, ie do NOT set this:

• Selecting this will prevent content from your service from being used as a Sonos alarm. This is useful if you have transient streams (such as live events, limited-edition content, and others).

Thanks for the information. Your extensive knowledge is appreciated! However I just want to use Sonos and have no desire at this time to get involved at that level with a music service. 

Thanks, but you are a customer of AccuRadio, so you should ask them to fix their service. Point them to this thread for details. They can PM me if they need further info.