Based on thunderbird docs, current nginx config need modified as :
server {
listen 80;
listen [::]:80;
server_name domain.com;
root /tmp/invalid-path-nothing-here;
# Improve privacy: Hide version an OS information on
# error pages and in the "Server" HTTP-Header.
server_tokens off;
location = /mail/config-v1.1.xml {
alias /var/lib/mailinabox/mozilla-autoconfig.xml;
}
# Redirect using the 'return' directive and the built-in
# variable '$request_uri' to avoid any capturing, matching
# or evaluation of regular expressions.
#return 301 https://domain.com$request_uri;
}
But failed to do so as it always redirect into 443/https, can you please add proper thunderbird autoconfig?, it needs to be on port 80 not 443.