name@example.com
   The mail server could not deliver mail to name@example.com.  The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.

I'm migrating from one hosting company to another. I need to fix any problems with my new mailservers before I make them live. But I'm having a problem with Thunderbird. It seems to be ignoring the hosts file and trying to access my old mailservers. Details: I'm trying to use the hosts file on Windows to allow me to send an email to (say) example.com using Thunderbird. This makes sense because I actually have an email server at the IP address (it is a new account at a new hosting company that I am migrating to). I just have not yet connected the new hosting company zone DNS at the domain registry. I made an Addon domain for example.com (not the real domain name) using cPanel, and created a new email account for name@example.com using cPanel. Here is the new line in the hosts file: 1.1.1.1 example.com I'm using 1.1.1.1 and example.com here, but the actual data is different, of course. I've also tried adding 1.1.1.1 mail.example.com 1.1.1.1 pop.example.com 1.1.1.1 pop3.example.com In all these cases, my sent email is returned to sender with an error message like the following: [code] name@example.com The mail server could not deliver mail to name@example.com. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries. Reporting-MTA: dns; root.springtimesoftware.com Action: failed Final-Recipient: rfc822;name@example.com Status: 5.0.0 [/code] If this is a known bug (which I guess is possible), what is the workaround? Can I somehow use my new IP address as the mailserver name or the destination address or something? ==== Windows 10 Home TB 60.9.0