NC17 - Talk - Firefox-Console - SyntaxError: expected expression, got '<'

I am facing an issue with “Talk”.
I had the issue with my test installation of NC16 but I have reproduced the issue again on a fresh installed NC17.0.0 (not upgraded from NC16) and I have only installed the Talk app from the webgui.

RaspberryPi 4, 4GB, OS on SSD

Firefox / Chrome
I am not able to conect to the turnserver. When I click on “check server” nothing happens. I see no incoming IP packages on the server (checked with IPtrace, but if I connect via netcat (nc) then the packages are received (TCP & UDP tested) and if the loglevel is set to “Verbose” in the turnserver config, then I can see the incoming requests as well (even if they have no meaning). Therfore there is no network issue.

Next investigation was to check the client side on serveral webbrowsers (FF & Chrome)
The deveoper console has shown two errors on the URL:
1st could be fixed by removing “add_header X-Content-Type-Options “nosniff” always;” fron nginx vhost config, which isn’t nice. Now I am getting the message:
Das Skript von “https://domain/apps/files/” wurde geladen, obwohl sein MIME-Typ (“text/html”) kein für JavaScript gültiger MIME-Typ ist. (in file https://domain/settings/admin/talk)

2nd error still persists:
“SyntaxError: expected expression, got ‘<’” (in file
I have no clue whyi see this error. This file cannot be found in this location. Only these files are there:
ll /var/www/domain/apps/spreed/js/admin/
total 2484
-rw-r–r-- 1 www-data www-data 554733 Oct 3 21:21 allowed-groups.js
-rw-r–r-- 1 www-data www-data 81417 Oct 3 21:21 commands.js
-rw-r–r-- 1 www-data www-data 468833 Oct 3 21:21 general-settings.js
-rw-r–r-- 1 www-data www-data 474201 Oct 3 21:21 signaling-server.js
-rw-r–r-- 1 www-data www-data 472642 Oct 3 21:21 stun-server.js
-rw-r–r-- 1 www-data www-data 481740 Oct 3 21:21 turn-server.js

I hope that someone has an idea, because I have no ideas to fix the issue.

Best regard Tilmann