This error may be due to your internet connection. Check if it works and try rebooting your router if you're experiencing network issues.
If your internet connection works fine, open Windows Firewall and in "Allow an app or feature through Windows Defender Firewall", click on Change settings, then add Outlook in the allowed apps list.
Try increasing the server timeouts setting in Outlook by going to File > Account Settings > Account Settings. Select your email account and click More Settings. In the Advanced tab, under "Server Timeouts", drag the slider to the right and save the changes.
If you still get this error, try starting Outlook in safe mode. Press the Windows + R keys, next type Outlook.exe /safe in the field and click Ok.