Reader and card
Reconnect the reader directly to another USB port and verify that the eID client sees the reader and card. Test another supported CCID reader if possible.
Certificate and codes
Check that the qualified signing certificate is valid. Select the signing certificate rather than the authentication certificate. Do not repeatedly guess BOK or KEP PIN.
Software and isolation
Update and restart the eID client and signing components, close competing smart-card applications and test a simple PDF in an official signing environment.
When to visit the Police
Visit a Police document department if the card is not recognised with a working reader, certificates cannot be issued or renewed, codes are blocked or the chip may be damaged.