You’ve not said whether you’re getting any error messages when you try to create the stereo pair? Are both speakers visible in the app? Have you followed the instructions here: https://support.sonos.com/en-gb/article/create-a-stereo-pair?utm_source=doc-care&utm_medium=stereopairs&utm_campaign=en-gb-doc-care-stereopairs
I notice many complaints online; are these things just junk and should I be avoiding Sonos products like the plague?
As an owner (for several years) of five Symfonisk speakers (two bookshelf pairs and one wall-mount single) I can say that they are not just junk - they can, if my experience is anything to go by, be made to work well.
Assuming that you’ve followed the instructions that nik9669a points to above and they are showing correctly in the app, the most likely reason for one or both dropping out is that wi-fi reception is marginal where they are located. The problem (in my experience) tends to manifest itself very much more noticeably if you are trying to play High Definition (i.e. high bitrate/large bit depth) material, simply because it involves larger amounts of data.
Solving it can require a lot of work if you have other Sonos speakers, but if they are the only two, it may simply be a matter of arranging your wi-fi access point(s) closer, and/or hardwiring one or more of your speakers.
I too have a pair or Gen 1 bookshelf speakers and they have behaved impeccably.
Are the ones you are pairing the same type and generation of speaker. Ikea made some revisions to their ranges over the years.
