diff --git a/docker-compose.yml b/docker-compose.yml
index 4b1bece..01cd4fd 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -33,7 +33,7 @@ services:
       MONGO_AUTH_SOURCE: ${MONGO_AUTH_SOURCE:-mqtt}
       MONGO_URL: ${MONGO_URL:-}
       MONGO_DB_NAME: ${MONGO_DB_NAME:-mqtt}
-      HUBOT_DISCORD_PERMISSION_GUILD_ID: ${HUBOT_DISCORD_PERMISSION_GUILD_ID:-}
+      HUBOT_DISCORD_PERMISSION_GUILD_ID: ${MQTT_ADMIN_GUILD_ID:-}
       MQTT_ADMIN_GUILD_ID: ${MQTT_ADMIN_GUILD_ID:-}
       MQTT_ADMIN_ROLE_IDS: ${MQTT_ADMIN_ROLE_IDS:-}
     extra_hosts:
diff --git a/scripts/lib/discord-role-permissions.js b/scripts/lib/discord-role-permissions.js
index 18958fa..1e6f9de 100644
--- a/scripts/lib/discord-role-permissions.js
+++ b/scripts/lib/discord-role-permissions.js
@@ -64,12 +64,12 @@ function hasAnyRole(roleCollection, roleIds) {
 
 function getPermissionGuildId(context) {
   const rawMessage = getRawMessageFromContext(context);
-  return String(
-    process.env.HUBOT_DISCORD_PERMISSION_GUILD_ID
-      ?? process.env.MQTT_ADMIN_GUILD_ID
-      ?? rawMessage?.guildId
-      ?? "",
-  ).trim();
+  return [
+    process.env.MQTT_ADMIN_GUILD_ID,
+    rawMessage?.guildId,
+  ]
+    .map((value) => String(value ?? "").trim())
+    .find(Boolean) ?? "";
 }
 
 export function createDiscordRolePermissionProvider(robot) {
diff --git a/test/discord-role-permissions.test.js b/test/discord-role-permissions.test.js
index 17939d8..07dcc22 100644
--- a/test/discord-role-permissions.test.js
+++ b/test/discord-role-permissions.test.js
@@ -79,6 +79,21 @@ test("Discord role permission provider fetches configured guild membership for D
   assert.equal(await provider.hasRole(null, ["env:MQTT_ADMIN_ROLE_IDS"], createContext({ guildId: null })), true);
 });
 
+test("Discord role permission provider falls back when permission guild env is empty", async () => {
+  process.env.HUBOT_DISCORD_PERMISSION_GUILD_ID = "";
+  process.env.MQTT_ADMIN_GUILD_ID = "929659839196561419";
+  process.env.MQTT_ADMIN_ROLE_IDS = "1";
+  const robot = createRobot();
+  robot.fetchedGuildMembers.set("505598218306977793", {
+    roles: {
+      cache: new Map([["1", { id: "1" }]]),
+    },
+  });
+  const provider = createDiscordRolePermissionProvider(robot);
+
+  assert.equal(await provider.hasRole(null, ["env:MQTT_ADMIN_ROLE_IDS"], createContext({ guildId: null })), true);
+});
+
 test("installDiscordRolePermissionProvider installs provider once", () => {
   const robot = createRobot();