A site i have been using is giving a a errer message SSL-Error_No_Cyper_overlap

Is this a modern site that might have been updated with especially strict security parameters, or is it an older site that might have obsolete connection settings that Firefox no longer supports? You can get information about the cyphers the web server uses by submitting the server name on the following test page: https://www.ssllabs.com/ssltest/.