Electrum loading/synchronizing transactions never completes


I am using the latest Getumbrel version on my Raspberry Pi 4 with 8 GB RAM and a 1 TB SSD.

When I am using the local IP as server with Electrum, my wallet (which has quite a few transaction in its history) starts loading them really slowly but never finishes.

Please see the attached photo:

It takes somewhere between 30 and 60 seconds until the syncronizing… reaches 449/449 and then it stalls.

If I then choose another external server, everything loads within 2-3 seconds maximum.

Any idea how to fix this?
Help is much appreciated.