Admin page error

1. The problem I’m having:

When I browse to the admin page I get an error. I’m on the server machine. The way I read the log, there should be no issue accessing the admin endpoint:
2026/06/13 17:45:17.731 ← [34mINFO<-[0m admin admin endpoint started {“address”: “localhost:2019”, “enforce_origin”: false, “origins”: [“//[::1]:2019”, “``//127.0.0.1:2019``”, “``//localhost:2019``”]}

2. Error messages and/or full log output:

{"error":"client is not allowed to access from origin ''"}

2026/06/13 21:59:52.936 ←[31mERROR←[0m  admin.api       request error   {"error": "client attempted to make request by disabling same-origin policy using no-cors mode", "status_code": 400}

3. Caddy version:

2.11.4 AMD x64

4. How I installed and ran Caddy:

caddy run

a. System environment:

Windows 10 x64

b. Command:

http://localhost:2019/admin
or /config
or /debug

c. Service/unit/compose file:

PASTE OVER THIS HERE IN THIS CODE BLOCK.
Please ensure it looks nice.

d. My complete Caddy config:

sub.anythingyoulike.com:8443 {
	reverse_proxy :81
}

5. Links to relevant resources:

Type here