post by email and finding the port

So I’ve been having trouble with the post by email feature.

I suspect that my problem is finding the correct port. In other email addresses that I’ve set up under this domain, in trying to make them work on Thunderbird/Outlook, it’s taken three or four tries to find the correct port. So here are my questions:

1)Could I find the correct port by setting up this email account in Thunderbird?
2)If I was to find the correct ports, does wordpress need the input or output port?

Thanks!

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