The firewall may have to be modified. To allow AnyDesk for incoming connections, add AnyDesk to the Whitelist:
"Is it possible to get the IP adresses from your servers for my firewall?"
We do not provide IPs from the AnyDesk network since these are constanly changing, but you can determine them yourself with:
"nslookup relays.net.anydesk.com" (Windows) or
"dig relays.net.anydesk.com" (Linux)
Windows FirewallIf the TCP-Listening Port is enabled on AnyDesk clients that are not yet installed hence run portable, the Windows Firewall will asked for permission on the first session request. Disable the TCP-Listening Port in your custom client to avoid the message for portable clients.
If AnyDesk cannot establish direct connections automatically you may set up a listening port manually in your firewall. Enter the port to the AnyDesk settings. See Listening Port