doh/dot servers give an error when checking

[AlexMSemo]

Hi! I have proxmox VE and Adguard Home LXC on it. Trying to configure DNS. When I fill just one DOH https://dns.cloudflare.com/dns-query I can pass the test. But if I fill more servers, f.e. https://dns.google/dns-query I get fail "The server "https://dns.google:443/dns-query ": cannot be used, please check the spelling". Writing it as an IP also doesn't help.
Could you please tell me what the issue might be?

[AlexMSemo]

The problem was with my Keenetic router, which had DNS query transit disabled:
dns-proxy intercept enable