The "Learn more" link points here: https://support.mozilla.org/en-US/kb/se ... =inproductSecure Connection Failed
An error occurred during a connection to www.mtgnexus.com. The OCSP response does not include a status for the certificate being verified.
Error code: MOZILLA_PKIX_ERROR_OCSP_RESPONSE_FOR_CERT_MISSING
The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
Please contact the web site owners to inform them of this problem.
One guide I found basically says "hey, i'ts your own browser's fault! just reinstall your browser or disable OCSP sampling" but safe to say I'm not doing that.