Guide to setting up Proton Bridge with Vivaldi Mail

[unrenowned]

This one had me for a while so thought I would create a quick write up.
If you're reading this then you are probably wondering how do I set up Vivaldi Mail with
Proton Bridge.

My setup is:
Ubuntu 24.04.1
Proton Bridge 3.13
Vivaldi 6.9.3447.44

Open Proton Bridge turn on the Beta Access settings and drop down to Advanced Settings.
Connection Mode -
IMAP - SSL
SMTP - StartTLS
Export TLS Certificates > Export

The TLS Certificates exports both key and cert in separate pem files.
Write them to a single file:

cat cert.pem key.pem > protonMail.pem

This file needs to be imported to Vivaldi to sign the localhost TLS connection to the bridge so that Proton Bridge trusts the Vivaldi connection. It's a self signed certificate however that's fine since all is happening on localhost.

Chromium based browsers have a cert store under ~/.pki called nssdb.
Add the protonMail.pem to the store by using certutil.

FIrstly, if not installed install certutil as shown:

sudo apt install libnss3-tools

Then add the certificate to the store:

certutil -d sql:$HOME/.pki/nssdb -A -t "CT,C,c" -n "protonBridge.localhost"
 -i protonMail.pem

Then restart Vivaldi and go to
vivaldi://settings/certificates
under the Authorities Tab the org-Proton AG trusted self signed certificate should be showing.

At this point Vivaldi Mail can be reopened and the Manual Setup can be filled in taking the settings verbatim from those shown in Proton Bridge.

[Insights]

I'm running a Debian based Linux Distro
PureOS 10 (Byzantium)
https://www.pureos.net

I have followed the directions as described in terms of
"Open Proton Bridge turn on the Beta Access settings and drop down to Advanced Settings.
Connection Mode -
IMAP - SSL
SMTP - StartTLS"
"Export TLS Certificates > Export"

I exported this to the Home Directory (not sure if that is correct)

In the home directory I do see 3 new files:
key.pem
cert.pem
protonMail.pem

I ran the command
cat cert.pem key.pem > protonMail.pem
but it didn't ask me for the User Password and didn't seem to do anything. I then ran
sudo cat cert.pem key.pem > protonMail.pem
and was prompted for the User PW which I entered.

I then ran
sudo apt install libnss3-tools
and that seemed to install fine.
Output is below:
teddy@teddy1:~$ sudo apt install libnss3-tools
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following packages were automatically installed and are no longer required:
libfuse3-3 libtext-csv-perl libtext-csv-xs-perl libwpe-1.0-1
libwpebackend-fdo-1.0-1 python3-proton-vpn-connection
python3-proton-vpn-killswitch python3-proton-vpn-session
Use 'sudo apt autoremove' to remove them.
The following NEW packages will be installed:
libnss3-tools
0 upgraded, 1 newly installed, 0 to remove and 89 not upgraded.
Need to get 1,026 kB of archives.
After this operation, 4,909 kB of additional disk space will be used.
Get:1 https://repo.pureos.net/pureos byzantium/main amd64 libnss3-tools amd64 2:3.61-1+deb11u3 [1,026 kB]
Fetched 1,026 kB in 7s (137 kB/s)
Selecting previously unselected package libnss3-tools.
(Reading database ... 216901 files and directories currently installed.)
Preparing to unpack .../libnss3-tools_2%3a3.61-1+deb11u3_amd64.deb ...
Unpacking libnss3-tools (2:3.61-1+deb11u3) ...
Setting up libnss3-tools (2:3.61-1+deb11u3) ...
Processing triggers for man-db (2.9.4-2) ...

I then ran
certutil -d sql:$HOME/.pki/nssdb -A -t "CT,C,c" -n "protonBridge.localhost"
-i protonMail.pem

but never got an output just a blinking cursor.

I Quit Vivaldi and reopened it.

When I then tested the Vivaldi mail setup with Proton Bridge, I got the error:
Login for 1027.0.0.1 failed. IMAP connection encountered an error! Error: Socket closed unexpectedly!

I would appreciate any clarification or support to make this work. I'm guessing something about the certutil command did not work, but not sure what to do about it. Thank you.

[Insights]

Correction - the error was When I then tested the Vivaldi mail setup with Proton Bridge, I got the error:
Login for 127.0.0.1 failed. IMAP connection encountered an error! Error: Socket closed unexpectedly!

[Insights]

I hope this helps someone else. I found a solution on the Purism forum and this may apply to users of other Debian based systems:
Here is a link to the forum solution and I'll put the important instructions here as well:
https://forums.puri.sm/t/command-hanging-trying-to-get-proton-bridge-to-work-in-vivaldi-browser-on-pureos-librem-14/26438

You ran sudo cat cert.pem key.pem > protonMail.pem, which may have caused the output file to require root permissions to access it using Vivaldi.

Delete the current protonMail.pem, regenerate it without prepending sudo, then perform the certutil command again:

These are the commands:

sudo rm protonMail.pem

cat cert.pem key.pem > protonMail.pem

certutil -d sql:$HOME/.pki/nssdb -A -t "CT,C,c" -n "protonBridge.localhost"
-i protonMail.pem

Open Vivaldi and go to vivaldi://settings/certificates. If the self-signed certificate is there under the Authorities tab, remove it, then rerun the certutil command.
(NOTE: I had to enter
chrome://settings/privacy
and then click on the "Security" tab and then click on "Manage certificates" to find the certificates)

The self-signed certificate is named org-Proton AG, so if is not listed, you have two options:

1. Press the Import button and select protonMail.pem, then open Vivaldi Mail. (NOTE: I did this option and it worked)

2. Uninstall and reinstall Vivaldi, then refollow the instructions from the beginning without any potentially breaking changes.

[aalkhater]

@unrenowned

Apologies for reviving this old thread. I followed these steps and managed to get the certificate exported from protonMail-bridge and imported using certutil. But I still get a "Login failed: no such user" error. I'm a little stuck. I would appreciate any thoughts as to why this may be happening?