Live from hack, Secure Website Certificate Verification:
To work around the OCSP error, you may temporarily disable OCSP certificate validation.
a. At the top of the Firefox window, click on the Tools menu and select Options...
b. Click on the Advanced icon to open the Advanced panel.
c. Click on the Encryption tab.
d. Click on Validation. The Certificate Validation window will appear.
e. Click Use the Online Certificate Status Protocol (OCSP) to confirm the validaty of certificates to un-select it.
f. Close the Certificate Validation window.
g. Click OK to close the Options window