I have precisely the same problem, although I've been using the apple earbuds that came with every iPhone 6.
Also, my phone is the xa1 ultra, which I bought brand new roughly a year ago. Never had an issue (mic and buttons dont work but that was to be expected from apple earphones on androids). Couple of days ago, this issue started. Exactly the same "not supported" message, stating I should contact Sony online support. I've reset the phone to factory settings, having to reinstall over 20gbs on apps, mainly. Before that, I've switched off and on, obviously, which didn't work, also. I love the quality of sound of the apple earphones, regardless of non-functioning buttons and mic. I'd hate to have to spend money replacing them, really. As a previous user wrote, I've been with Sony for many many years, since the Sony Ericsson times. I've had sony's for over 15 years now (I had the t68i, the first with a camera). If I have to start having issues, there's plenty of competitors in the market that produce phones without all the known issues that Sony has had of late in its many phone models.
Can anyone from tech support give an idea or make an update that can sort this issue? Clearly, there's a lot of people with this problem, with different models as well as many other problems, I can see... If you go to the Samsung, Apple, one+, huawey, ztc, etc, etc, etc, you don't see these many complaints. Either you go cheaper and you understand these issues or, if you want to keep the Sony prices and brand association, fix this. The Sony mobile of late, unfortunately, is nowhere near the quality that Sony video, audio and games clearly show. For the first time, I'm really regretting having bought this piece of junk... It looks that you are now building phones to last 6 months, tops. After that, it's problem after problem.... I'm only writing about the earphone jack because its the latest and most annoying. Because 6 months after I bought this piece of crap (for almost 400 euros, what a waste of money ..) the touchscreen started malfunctioning. Even today, sometimes, completely randomly, it's like a ghost starts touching my screen, pulling the drop down menu whenever it feels like it.
