"Unknown Error" UnsuccessfulResponseException: HTTP response: 502

This is currently only happening on my Onyx Boox Poke 3, things seem to be working on the Pixel 7a.

When syncing the app, I get a notification with the error info listed below, and the ability to copy it to the clipboard.

I have not yet tried logging out and logging back in, as there are some annotations I want to try to keep, but I will try that as well.

Unknown error
wallabag.apiwrapper.exceptions.UnsuccessfulResponseException: HTTP response: 502
Stacktrace:
wallabag.apiwrapper.exceptions.UnsuccessfulResponseException: HTTP response: 502
at wallabag.apiwrapper.WallabagService.checkResponse(WallabagService.java:1525)
at wallabag.apiwrapper.WallabagService.checkResponseBody(WallabagService.java:1503)
at wallabag.apiwrapper.WallabagService.execAndCheckBody(WallabagService.java:1499)
at wallabag.apiwrapper.WallabagService.lambda$modifyArticle$7$wallabag-apiwrapper-WallabagService(WallabagService.java:868)
at wallabag.apiwrapper.WallabagService$$ExternalSyntheticLambda4.run(D8$$SyntheticClass:0)
at wallabag.apiwrapper.NotFoundPolicy.call(NotFoundPolicy.java:140)
at wallabag.apiwrapper.NotFoundPolicy.call(NotFoundPolicy.java:133)
at wallabag.apiwrapper.NotFoundPolicy.call(NotFoundPolicy.java:128)
at wallabag.apiwrapper.WallabagService.modifyArticle(WallabagService.java:868)
at wallabag.apiwrapper.ModifyArticleBuilder.execute(ModifyArticleBuilder.java:103)
at wallabag.apiwrapper.ModifyArticleBuilder.execute(ModifyArticleBuilder.java:86)
at fr.gaulupeau.apps.Poche.service.workers.OfflineChangesSynchronizer.syncArticleChange(OfflineChangesSynchronizer.java:368)
at fr.gaulupeau.apps.Poche.service.workers.OfflineChangesSynchronizer.syncOfflineQueue(OfflineChangesSynchronizer.java:118)
at fr.gaulupeau.apps.Poche.service.workers.OfflineChangesSynchronizer.synchronize(OfflineChangesSynchronizer.java:68)
at fr.gaulupeau.apps.Poche.service.tasks.SyncOfflineChangesTask.run(SyncOfflineChangesTask.java:17)
at fr.gaulupeau.apps.Poche.service.tasks.ActionRequestTask.run(ActionRequestTask.java:25)
at fr.gaulupeau.apps.Poche.service.TaskService$$ExternalSyntheticLambda2.run(D8$$SyntheticClass:0)
at fr.gaulupeau.apps.Poche.service.TaskService.run(TaskService.java:162)
at fr.gaulupeau.apps.Poche.service.TaskService.$r8$lambda$7B6NdHPPL8YMNadJyfVPhGC-s2M(Unknown Source:0)
at fr.gaulupeau.apps.Poche.service.TaskService$$ExternalSyntheticLambda1.run(D8$$SyntheticClass:0)
at java.lang.Thread.run(Thread.java:919)

Start with OfflineChangesSynchronizer.java at syncArticleChange and follow the WallabagService response checks at lines 1499-1525. Reproduce offline synchronization on the Poke 3 while comparing the Pixel 7a behavior and available server responses; done means the cause of the 502 is identified and the sync reports or handles it appropriately.

Written by the indexing model from the issue text.