CUPS printer becomes unavailable

[pentastich]

Hi! I'm experimenting with Android CUPS Print on my Google Pixel 4 XL phone. It's running Android 11.

After some messing around, I was able to get the app to discover my printer and I can print to it (so I must have SSL set up). However, the next time I go to print, I initially get the preview and print button. Then, after a second or two, the screen switches to "This printer isn't available right now" and I see a small popup saying "Search found 1 printer".

If I open the select printer dialogue, and select "All Printers…", then select my printer, I get the preview and blue printer icon, and can, in fact, print.

One other, possibly unrelated, issue is that although my printer can print duplex, and CUPS knows that it can print duplex, and Avahi Discover appears to think it can print duplex, the "Two-sided" option is greyed out.

In case it helps, here's what "Avahi Discovery" reports for my printer:

Service Type: _ipp._tcp
Service Name: Office Printer @ nasty
Domain Name: local
Interface: enp36s0 IPv4
Address: nasty.local/192.168.86.238:631
TXT TLS = 1.2
TXT priority = 0
TXT URF = DM3
TXT note = Office
TXT rp = printers/Office
TXT printer-type = 0x105E
TXT ty = EPSON WorkForce 645, driverless, cups-filters 1.27.4
TXT Duplex = T
TXT qtotal = 1
TXT Copies = T
TXT product = (EPSON WorkForce 645)
TXT printer-state = 3
TXT pdl = application/octet-stream,application/pdf,application/postscript,image/jpeg,image/png,image/pwg-raster,image/urf
TXT Color = T
TXT adminurl = https://nasty.local.:631/printers/Office
TXT txtvers = 1
TXT UUID = 6b053119-918b-3453-6c37-22dc10e48886

My CUPS server is hosted on a device running Ubuntu Server 20.04.1.

If there's any other info that would be helpful, please let me know. This is a home system and I can try all sorts of things.

Thanks!

Jim

[fungs]

Also here (Android 7) I cannot select duplex printing and if the printer is not in status 'not connected' it prevents me from printing.

Usually from other clients, I print to the cups server and later turn on the printer which then prints everything in the queue. This doesn't work with this Android client.