Hi @jeffrey93
Welcome to the Sonos Community!
If you play music to your Beam from an online music service, does it play without issue? If so, then I can only advise that AirPlay also needs a good connection between your iPhone and your router - it might be best to keep your iPhone out of your pocket and in one location while playing AirPlay to the Beam. If you have a glass coffee table, it might be a good idea to keep the iPhone off of that too.
If, however, playback from an online service is not faultless, then I recommend you get in touch with our technical support team, who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports. In this case it’s likely due to electromagnetic interference so it may help to check our Reducing wireless interference help page first. The most common error people make is having WiFi devices too close to their router (you want at least 1m separation).
I hope this helps.
Edit: I just realised you mentioned that your Beam is ethernet-wired. Please ignore my second paragraph (other than the part about contacting tech support if needed).