Nitrokey Pro: GPG won't/can't access keys on different computer


I have a Nitrokey Pro and on it have some GPG keys. It works fine on one computer, however, when I try to use it on another computer, it won’t sign anything:

gpg --status-fd=2 -bsau 0xDC6A2D9E14F91CF72D6480ECF1D8EDE96F0E3E28

It opens a pinentry window, asking me to:

Please insert the card with serial number:
0005 000030FF

I have my card plugged in, but choosing “Ok” just repeats the prompt, choosing “Cancel” exits the screen and I get “gpg: signing failed:” as error.

dmesg shows the following for my card:
[96174.309807] usb 1-8: new full-speed USB device number 15 using xhci_hcd
[96174.580290] usb 1-8: New USB device found, idVendor=20a0, idProduct=4108
[96174.580291] usb 1-8: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[96174.580292] usb 1-8: Product: Nitrokey Pro
[96174.580293] usb 1-8: Manufacturer: Nitrokey
[96174.580294] usb 1-8: SerialNumber: 000030FF0000000000000000
[96174.593274] input: Nitrokey Nitrokey Pro as /devices/pci0000:00/0000:00:01.3/0000:01:00.0/usb1/1-8/1-8:1.0/0003:20A0:4108.000B/input/input22
[96174.644826] hid-generic 0003:20A0:4108.000B: input,hidraw4: USB HID v1.10 Keyboard [Nitrokey Nitrokey Pro] on usb-0000:01:00.0-8/input0

I notice the serial number looks similar, but not identical, to the one pin entry displayed.

Furthermore, I copied over my .gnupg from my other computer to this computer. Does any of this cause my problems?

Any ideas on how to proceed?

Oh, I also have this issue which probably is related:

$ LANG=C gpg --card-status
gpg: selecting card failed: No such device
gpg: OpenPGP card not available: No such device


Most probably other service is using your smart card right now, which is not sufficiently communicated. My guess is that pcscd is blocking. If you are using modern Linux, then this should help:

$ systemctl stop pcscd pcscd.socket

Please try again after executing this one.