Need help with HAProxy, pfsense, Truenas Core to get Photoprism working

Hi there,

I am stuck with the installation of Photoprism as app (docker) on TruenNAS Scale behind pfsense.

I installed HAproxy, forwarded both HTTP+HTTPS ports to a virtual IP.

When I try to access Photoprism via my website I receive the error:

An error occurred while connecting to photoprism(dot)mywebsite(dot)com. SSL received a record that exceeded the maximum permissible length.

Error code: SSL_ERROR_RX_RECORD_TOO_LONG

In frontend HAProxy listens to the virtual IP on port 443 (HTTPS), use SSL Offloading, has a Letsencrypt certificate. Forwardfor option enabled. In backend is the the IP of my TrueNAS followed by the port of the Photoprism Application.

I toggled SSL Encryption, SSL checks, SSL Offloading, Forwardfor but no change.
I assume that the problem is with the certificate so my question is how can I let HAProxy completely ignore SSL Checks.

Many thanks!