I honestly don't understand all that networking stuff, but I think an internal server error is much as it says - a problem at the server end.
Having said that, the fact that the affected page works fine on your other equipment suggests that there is something different about your gadget that the server can't handle/identify.
You could try waiting it out and see whether the site owner identifies and rectifies a problem. You could also try a few things in your own browser, in case it's upsetting the server - more suggestions in this link:
https://askleo.com/whats_an_internal_server_error_and_how_do_i_fix_it/
Essentially, the usual business - clear cache and cookies, try another browser, refresh the page...
Hopefully, somebody with a clearer understanding of this will happen along with the solution.
