How do I get Thunderbird to stop trying to access a cancelled email provider.

I have a couple of old email providers in my Thunderbird that I can now longer access as they have been cancelled. I want to keep the emails but don't want Thunderbird to keep trying to access those deleted server accounts. Anyone know how I can keep these emails in Thunderbird but not have Thunderbird keep trying to access those servers. Those servers still exist but keep asking for a password and a spinning circle keeps showing up like something is running which I'm presuming it's trying to talk to those servers.