Firefox and SEC_ERROR_REUSED_ISSUER_AND_SERIAL

[Raouni]

Hello! I can access only one of my two Truenas-servers as the browser says its certificate is the same as another.
Hence giving me the SEC_ERROR_REUSED_ISSUER_AND_SERIAL error.

If i remove the certificate in Firefox i can access the other server but then the first is inaccessible and vice verse.

Any tips how to solve this?