Hi Marc, I’m sorry to hear you’re having issues getting your stream working smoothly. Please follow @AceRimmer advice but perhaps start at least halfway through the thread the first part is not applicable anymore. I’ve left mine in the AIO mode and it’s working very well feeding spdif to my Denon AVR. It does seem that many folks have some teething pains early on, I find iFi products are good but the multiple functions and wonky documentation can be confusing.
Best luck with it
This thread also shows how initial setup can be tricky