diff --git a/docs/usage/self-hosted-configuration.md b/docs/usage/self-hosted-configuration.md
index 9325e2562e432e8d87b3ae03c2382e3850109e01..06dca5a0ab4a1b1939d92765a7b6a65a581805aa 100644
--- a/docs/usage/self-hosted-configuration.md
+++ b/docs/usage/self-hosted-configuration.md
@@ -503,7 +503,7 @@ The format of the environment variables must follow:
 
 - Datasource name (e.g. `NPM`, `PYPI`) or Platform name (only `GITHUB`)
 - Underscore (`_`)
-- `matchHost`
+- `matchHost` (note: only domains or subdomains are supported - not `https://` URLs or anything with forward slashes)
 - Underscore (`_`)
 - Field name (`TOKEN`, `USERNAME`, `PASSWORD`, `HTTPSPRIVATEKEY`, `HTTPSCERTIFICATE`, `HTTPSCERTIFICATEAUTHORITY`)