macbook pro disconnects from map server

Macbook Pro running OS 10.8.5, 2.66 Ghz 4gb Ram.

Mac mail stops communicating with the Imap server, have to close program and re-open to receive latest emails.

Just switched email providers, all the other Macs OK, just two MacBooks having issues.

All settings triple and Quad checked. Provider is Godaddy and workspace email.

Gets old after awhile opening and closing mail. Any Ideas from anyone. Macbook owners afraid to upgrade to El Capitan from Mtn Lion.

I suggested the upgrade could help. Company email service and two private MacBooks. One the owner and one owners son.

Any help is appreciated.

Thank you.