"Upload All" not working?

[xxxserxxx]

Version: 0.11.0 (33)
Server: PhotoBackup/server-go
App settings: Background data enabled; battery use is "unoptimized"
Android: Samsung One UI 4.1 (Android 12)

Selecting an individual image from the journal and doing a "Manual backup" works -- the file is received by the server. However, the "Upload All" function from the hamburger menu does nothing beyond showing the "Started to upload all pictures" message; there's no indication from the server reverse proxy that any request is sent to the server from the client.

Similarly, the app apparently never auto-uploads files, either with "Over Wi-Fi only" or "... or mobile network". Does the app start a service? Android shows an icon for every persistent (service) app, and I don't see one in my bar for PhotoBackup.