I have been using joplin for about 6 months. sync working ok, between iphone and two win10 computers. last night, adding a number if items on win10 computer (and deleting a couple of todo's that suddenly appeared, containing only code, how, I don't know) i found that new items were not syncing to iphone. nor from iphone to computer.
sync on iphone and computer claimed to be completing ok. iphone sync config test says Success! however this evening i am now getting error message on computer joplin, which is meaningless to me:
'Completed: 05/23/25 11:36 PM (26s)
Last error: FetchError: request to https://mia.nl.tab.digital/remote.php/dav/files/astro46%40fastmail.fm/Joplin/info.json failed, reason: write EPROTO 700160:error:100000f7:SSL routines:OPENSSL_internal:WRONG_VERSION_NUMBER:....\third_party\boringssl\src\ssl\tls_record.cc:130: "
Aside from fixing the problem,just the fact that it happened, with no error messages until this evening, and only on one device, is making me seriously reconsider using joplin. the notes that were supposed to sync last night from computer to iphone were necessary for work today. If i hadn't check iphone and saw that the notes had failed to sync, and copied them to paper to have with me, it would have been a big problem.
In sync settings, advanced settings, there is an option to ignore tls certificate errors when using Nextcloud / webdav. Try ticking that on both computer and iphone and see if it helps
Also I see from the error message you are using Tab Digital. Do you happen to be using the free plan?
Free nextcloud providers tend to be unreliable from what I have heard, but also if you are not in control of the nextcloud installation, providers can sometimes (though rare, and probably less likely to happen if you pay) introduce bugs which break the integration with software like Joplin.
Here is a recent example where Tab Digital introduced a bug that encrypted user data when encryption was not enabled:
that is not a good thought. but very possible, since I don't think anything changed at my end. the thread that you referenced, where files were mysteriously encrypted is closed for lack of responses. I can only assume that it was never fixed.
FYI your issue is not the same one as the one I posted a link to, but if you did not upgrade Joplin just before this happened, then it is most likely a problem on the Tab Digital side
i posted in nextcloud forum. I'll see if anything helpful comes of it. Another user posted that they use Nextcloud client to sync from windows computers. Since one of these devices is short on available memory, i'd rather not install another app to run constantly.