Shiny server error downloadable font: download failed

Hi everyone!
I recently setup a new server after we had to take down the old machine and I'm now trying to activate an app again that was running perfectly a year ago. The app is working fine if I run it from RStudio but immediately disconnects when I try to access it from the server although the app is displayed correctly as far as I can see).

No log files are created so I'm guessing that the R script is running fine and just terminating without an error. The Java console is giving me an 404 error for a font (awesome-font) that it isn't able to download. I only included awesome-font icons for a small menu and the icon are displayed there correctly. The error persists even if I use glyphicon for the icons or remove the icons altogether.

The app is available at http://141.40.217.80:3838/miREV/ and the error message was as follows:

This page uses the non standard property “zoom”. Consider using calc() in the relevant property values, or using “transform” along with “transform-origin: 0 0”. miREV

GET http://141.40.217.80:3838/favicon.ico [HTTP/1.1 404 Not Found 0ms]

GET http://141.40.217.80:3838/miREV/font-awesome-6.2.0/webfonts/fa-v4compatibility.woff2 [HTTP/1.1 404 Not Found 2ms]

downloadable font: download failed (font-family: "FontAwesome" style:normal weight:400 stretch:100 src index:0): status=2147746065 source: http://141.40.217.80:3838/miREV/font-awesome-6.2.0/webfonts/fa-v4compatibility.woff2

GET http://141.40.217.80:3838/miREV/font-awesome-6.2.0/webfonts/fa-v4compatibility.ttf [HTTP/1.1 404 Not Found 2ms]

downloadable font: download failed (font-family: "FontAwesome" style:normal weight:400 stretch:100 src index:1): status=2147746065 source: http://141.40.217.80:3838/miREV/font-awesome-6.2.0/webfonts/fa-v4compatibility.ttf

Wed Nov 16 2022 17:19:22 GMT+0100 (Central European Standard Time) [INF]: Connection opened. http://141.40.217.80:3838/miREV/ shiny-server-client.min.js:1:21816

Wed Nov 16 2022 17:19:22 GMT+0100 (Central European Standard Time) [DBG]: Open channel 0 shiny-server-client.min.js:1:5375

The application unexpectedly exited.

I'm guessing it could be a compatibility error between a fresh shiny server installation and an older app script but I cannot figure out what the problem is unfortunately. If anyone can give me a hint or point me to a solution, I would be very grateful.
Kind regards,
Benedikt