Homepod constantly looses connection to my itunes account

I have had to delete my Homepod and reset it three times in the last three weeks. After a week of working as it should, just like clock work, Siri can no longer play music when I request it. Although Siri responds that the music I requested is 'on its way' - no music plays from the homepod. I request it again - nothing. The really strange thing is if I go back to my iMac and play the music from there and select the homepod as a speaker it works fine. The problem seems to be that Siri looses access / connection to my itunes account and can not find the music any longer? I have a subscription to itunes in the cloud but I do not have an Apple Music subscription. Any suggestion why Siri on the Homepod keeps crashing and can't play my music when I request it?