Why is ISA Server not being detected?

Question

firewall

Good afternoon! Recently delivered to a network MS ISA Server 2006 SP1, on the computer - ISA Client.
I set up auto-discovery on ISA, and created allowing rules for interacting with the internal grid, I made a WPAD entry in DNS.
The ISA client cannot detect the server not only in automatic mode, but even if the server address is explicitly specified.
On the local machine with the ISA client, I changed the statically set address to DHCP, on the DNS server I deleted the WPAD entry from the global blocklist (dnscmd /config /enableglobalqueryblocklist 0), but this did not help either, ISA Server could not be detected. What am I missing? Where to look?