You can fix
Outlook Send / Receive Error by blocking the outgoing and incoming traffic, therefore ensure that Outlook and/or the appropriate ports for email are set as exceptions to allow traffic through.
If you encounter send/receive problems after upgrading Outlook, you'll need to adjust your firewall to enable Outlook to flow through once again.
This is because some firewall solutions use a hash to ensure that the file is passed through the firewall is the correct outlook.exe and not a virus posing as outlook.exe. Outlook.exe is updated, as is the case with most upgrades, and you'll need to approve it as safe once more. More information on this may be found in the handbook for your firewall solution.