Symptom: Loading the Scute security device in the security device manager of Firefox fails with "Unable to load module".
Solution: Make sure that Scute is correctly installed, and that
all libraries and executables are available. If you are using GnuPG
2.0 (instead of 2.1), you may need to make sure that the GPG Agent is
running and can be found via the environment variable
GPG_AGENT_INFO. See Invoking GPG-AGENT in Using the
GNU Privacy Guard, for details on how to run the GPG Agent.
Symptom: Client authentication fails with "<example.com> has received an incorrect or unexpected message. Error code: -12227".
Solution: Make sure that the correct OpenPGP card is inserted and the certificate available in GPGSM. Check that the OpenPGP card is detected correctly in the security device manager and the corresponding certificate is displayed in the certificate manager of Firefox. See Authentication With Service.
Symptom: The OpenPGP card is detected and displayed in the security device manager in Firefox, but no corresponding certificate is displayed in the certificate manager of Firefox.
Solution: Make sure that the corresponding certificate is imported in GPGSM.