First verify that your new LEAP is using the same IP address as before.
Try sending an email message from command line directly to verify nothing is blocking and gmail will accept mail directly from your machine.
If your sendmail has a queue built up, purge your queues.
I sent emails from the command line using sendmail. If I send to an internal address (in virtual domains) it works. If I send to an external address - gmail or an other email address I have access to it does not. Nothing in the mail queue either (although I am an amateur I had thought of that).
Mail systems require a variety of ways to validate your mail is coming from a valid email server.
Although you say you are using the exact same IP address as before, I suspect you are not, at least for gmail.
You can double check this more or less by sending your mail through your ISP’s designated SMTP relay (almost always, this is provided), if it succeeds then I’d say that almost certainly verifies this.
The other usual things apply…
Make sure your IP address doesn’t show up on any Open Relay SMTP blacklists.
Make sure your ISP has listed your IP address as authorized to be running a mail server (They need to modify their own public records accordingly).