My FreedomBoxes are now on Verion 26.4.
The RSPAMD error is not a problem, but because I discovered it, I’ll mention it: rspamd is not accessible anymore from mydomain.tld/rspamd/. instead I can reach it over the lan ip/rspamd/. And when I go to Apps in Plinth and open Postfix/Dovecot, then I also receive an error when I hit the button ‘Spam management’ (in German: Spam verwalten). Any suggestions?
You need to make sure that pfsense is forwarding the IMAP/POP/SMTP ports to appropriate FreedomBox machine. This is likely the timeout problem you are seeing.
/rspamd URL needs to be forwarded by your pfsense/HAProxy setup to FreedomBox with email server. This will fix the Spam management issue.
Also I see a problem with the setup. Let’s Encrypt certificate obtained by FreedomBox is also used for Posfix/Dovecot setup. If FreedomBox is unable to get proper certificate, a self-signed certificate is served making the setup insecure. You will need to find a way to forward ports for these ports or switch to a setup where FreedomBox can get proper LE certificates.