Error with BLAST against NCBI


When I try to perform a BLAST on a sequence against an online database, the following error message appears: “Internet exception occurred (12057): It was not possible to connect to the revocation server or a definitive response could not be obtained.”


This could be a temporary problem with NCBI, so please try again at a later stage to check the connection with NCBI again.

If the problem persists, it could be that Windows is not capable of checking the validity of the HTTPS/SSL encryption certificate (because Windows cannot connect to the revocation servers or the time is not correctly set on the computer, etc.). A workaround is to uncheck the option "Check for server certificate revocation" in Internet Explorer: Go to Internet Explorer > Tools > Internet Options > Advanced tab > Security options and uncheck "Check for server certificate revocation (requires restart)". Unchecking this option makes browsing of HTTPS website less safe, so we recommend to first discuss this issue with your IT department to check/solve the underlying cause. More information about Certificate Revocation Checks can be found here:


Applicable for: 
Version 1.0 - 7.6