Proxy configured, but extension application does not work

I have installed version Lucee on a Windows Server 2019. I am behind a proxy. I have configured the lucee-server.xml and added the entry <proxy enabled="true" port="8080" server=""/>. Updates are displayed under the web admin interface. The proxy setting worked, because I get updates displayed:

Only when I click on Extension->Application does it seem to go into an endless loop and it doesn’t go any further: