Treafik as reverse proxy

Nethserver 8
Modul Traefik (http routes)
Hi,
our web frontends run on servers in orange DMZ and have the same name syntax:
bbbb.yyy-zzzzzz.de
ccccc.yyy-zzzzzz.de

we try since about 2 weeks to find a solution for our B -webserver and E-webserver in green LAN
No problem to contact B-webserver
Only the E-Webserver (IIS on WIN2019) is like sorehead.
This is a web server in green LAN at IP 172.20.20.219.
At the time we had an port forwarding rule in firewall:
all port 7443 >> 172.20.20.219 port 443
That’s OK, but a long string to input:

https://xxxx.yyy-zzzzzzz.de:7443/eeweb

We thought, that we could in treafik simplify this long string to:

https://eeweb.yyyy-zzzzzzz.de

the config in TRAEFIK of B-Webserver is OK, but E-Webserver in the same green LAN and the similar configuration only shows the IIS-Site.
Where is our logical mistake ??

our structure

Structure 11/2024
							INTERNET stat.IP
                               |
							   |
                         [VDSL-MODEM]
                               |
                               | red
                         [ FIREWALL ]
                orange-DMZ|    |   |blue (WLAN)
      ____________________/    |    \___________
      |         |              |                \              /°))))
 [NETHSERVER8]  |     		 green_172.20.20     [AccessPoint]/
   sogo nc |	       |
                |              |––––[B-Webserver] deb11__~.215
                |              | 
 [C-Webserver]––|              |––––[E-Webserver] Win____~.219
                |              |
 [PHONE-1]––––––|              |––––[A-Webserver] devuan_~.240    
                |              |
 [PHONE-2]––––––|              |––––
 [PHONE-3]––––––|              |––––
 [PHONE-4]––––––|              |––––

This is HTTP route to Webserver-B at 172.20.20.215 - this makes, what we want:
2024-11-08_HTTP-Route-B