When migrating your email hosting to a new service provider, the key change that needs to be made is to the mail exchanger record, commonly referred to as MX record. An MX record is the record on your domain that routes email traffic to the proper servers currently hosting your email. The essential switch from one email host to another occurs when the MX record is changed and that change propagates to the internet. This change will need to be made with the company where your domain is hosted.
Some common domain hosts are GoDaddy, Network Solutions, 1and1, and Emerald. One important question you would want to ask your domain host would be, "How long after making the change to my MX record before the change takes effect?" With some hosting companies the change is fairly immediate and occurs within a matter of minutes, but others can take up to several hours. Keeping that in mind, you will not want to change your mail client settings until the MX record change is verified.
Below you will find Redtail's MX record information (which is where the MX record for your domain should point if Redtail is hosting your email):
When changing web hosts, your MX record can be impacted. You will want to correspond with the new web hosting provider to ensure that your MX record is accurately reflected after the change over.
If you fail to timely renew your domain name, the provider generally removes the MX record. You will always want to ensure that your MX record was not impacted if your domain renewal happens to be late.
For instructions on configuring your MX record with GoDaddy, click here.