Thunderbird security exception popup

[uncertain]

My YunoHost server

**Hardware:
Old gaming computer. nividia 970 display card, 500gig crucial ssd, mbord: gigabyte GA-X58A-UD3R with 16gig of mem

**YunoHost version:
yunohost-bullseye-11.0.9-amd64-stable run from usb that was made using balenaEtcher-Portable-1.18.11
HDD was formatted using gparted-live-1.5.0-6-amd64

I have access to my server as admin
yes

Are you in a special context or did you perform some particular tweaking on your YunoHost instance ?
no

Description of my issue

Thunderbird keeps spamming me with the add security exception popup. I’m not using my server for email but did want to backup my address book and emails using nextcloud.

[rodinux]

First, did you get a valid let’s encrypt certificate for your domain ?

Also, you try do this in command line

sudo yunohost regen-conf postfix

For the adress book in Nextcloud, you can just export your adress books in Contacts (in Vcard)

If you just want a backup the emails, you can save all the folder /var/mail/ or sync this one on another mail server…

You can also sync your emails to export them on another email address using a tool like this one:

https://imapsync.lamiral.info/X/