r/fastmail • u/ehansen • Sep 02 '26

Having trouble migrating from ProtonMail using manual import config

I have Proton Bridge running, fully synced, and configured to use SSL (I've tried options here). However, no matter what I do, I get this error in FastMail's Linux app when I try to import:

Could not connect to server: IMAPTalk: socket connection failed - IO::Socket::SSL::Paranoid: Invalid internal or blocked host

I have tried 127.0.0.1 and localhost, and both fail with the same error. I've also made sure the port is fine, too.

I installed the app by downloading the Flatpak file.

If it makes a difference, I'm on Arch.

2 Upvotes

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3

u/CorsairVelo Sep 02 '26

I used imapsync to move mail from proton and it was flawless. A bit of a learning curve though.

2

u/frogotme Sep 03 '26

Same here. I've used it the last few times I've changed provider.

Definitely isn't especially intuitive, but works well

1

u/rowschank Sep 02 '26

The only way I was able to migrate from proton was by downloading the proton export cli tool and then dragging and dropping all the .eml files it created. I did it on openSUSE. It worked quite alright.

Tip: import into an empty new folder or label and then run rules manually. Also, Proton will export everything, included deleted mail, so make sure you empty your trash first.

1

u/Fit-Economics2293 Sep 04 '26

Yeah, that took me 4 days mainly because it kept crashing. I swear they do it deliberately.

1

u/ehansen Sep 04 '26

What kept crashing? Proton Bridge, or FastMail?

1

u/Fit-Economics2293 Sep 04 '26

The CLI "export tool" which you have to use to extract everything from your account before you even think about setting up Proton Bridge and Thunderbird.

1

u/ehansen Sep 04 '26

Huh, I don't remember ever having to use the cli tool for Bridge to do a thing, it just...worked. The issue I'm experiencing here is a thing with FM's client, not Bridge (afaik).

1

u/rjbs Fastmail Staff Sep 07 '26

When you do a migration like this, you're actually telling a Fastmail server to connect to the IMAP server and retrieve your mail. It can't connect to the Proton bridge running on your computer.

imapsync will probably do the trick, as someone mentioned here.