Best answer as chosen by user xh7000: Tricky one
I would have assumed from the error message that this was a server error fault at GMail's end. It happens, and can even happen for one of your accounts and not the other.
But your deleting that account then re-adding it doesn't support that.
But if you have set the account up correctly according to GMail's setup instructions, not forgetting the correct port and SSL settings, and if the Webmail account settings has POP enabled and that has not been changed, this then points to a problem either with the OE software or again with the GMail servers.
Try this. Shut down OE. If you use OE at home and at work, make sure they are both shut down. Log in to this account's web access.
Now open OE and try this account again. Does the error still display?