Nextcloud account not uploading without carrier network connected

REPRODUCIBILITY (% or how often): always
BUILD ID = OS VERSION (Settings > About product): 4.3.0.12
HARDWARE (XA2, X10, X10 II, …): XA2
UI LANGUAGE: EN
REGRESSION: (compared to previous public release: Yes, No, ?):

DESCRIPTION:

I’m having issues with connecting to my provider since a few weeks. As a process for debugging the issue I want to reset my device. But when I want to create a back-up this is not uploaded to the cloud.

PRECONDITIONS:

Have no carrier network set active (sim removed).

STEPS TO REPRODUCE:

  1. Remove Sim
  2. Configure nextcloud account to back-up
  3. Create a back-up, once the process is completed no new file is added to the remote host

EXPECTED RESULT:

My file gets uploaded to the cloud

ACTUAL RESULT:

No file is added.

ADDITIONAL INFORMATION:

I’m using https://us.cloudamo.com/ as my Nextcloud host. This worked fine until recently that I ran into issues with my carrier.