Recently we had to renew an expired SSL certificate on our Exchange 2010 SP 1 RU 5, once we did this all of our Mac Outlook clients are coming up with the error " The server for account Account_Name returned the error "Logon failure: Unknown user name or bad password. Your username/password or security settings may be incorrect. Would you like to try re-entering your password"' in Outlook for Mac 2011.

We have tried to renew the certificate but it is still not working. The certificate has been renewed on the Exchange server, and Windows PC’s with Outlook are connected fine, however the Mac clients with Outlook for Mac receive the error message.  

We are able to access mail via OWA and Mac Mail without any issues on the Macs.

Other posts have suggested recreating the ‘EWS’ virtual directory on Exchange, however we are reluctant to do this as the Macs can authenticate successfully when browsing to the URL http://ExchangeCASServer/EWS/Exchange.asmx.

We have not yet changed the SMTP port as this has never affected anyone until now, also we have tested the Outlook client for Mac that has didn't have the previous certificate on it and it logs in without the error message.

Many thanks.