Hi @Jorgen Nielsen
As discussed by our smorgasbord of community experts here, there are several reasons why you could be experiencing the problems you describe.
I do recommend you test disabling the Crossfade feature, as suggested by @sjw, as there is a known bug regarding Crossfade and Spotify at present - if that solves the issue, I recommend you leave Crossfade disabled for the time being.
There is also the possibility that there are local network issues - if sources other than Spotify play without issue, it’s less likely that this is the case.
It’s also not impossible that there is a hardware-related issue - some of our older players now struggle with Spotify and a few other sources. Making your Connect a member of a group led by a newer player could resolve this for you.
For a definitive answer, however, 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 - the Connect’s logs should contain the answer.
I hope this helps.
"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein