diff --git a/src/runtime/server/lib/oauth/steam.ts b/src/runtime/server/lib/oauth/steam.ts
index a0e73870..e93f9d23 100644
--- a/src/runtime/server/lib/oauth/steam.ts
+++ b/src/runtime/server/lib/oauth/steam.ts
@@ -39,14 +39,14 @@ export function defineOAuthSteamEventHandler({ config, onSuccess, onError }: OAu
     }
 
     const url = getRequestURL(event)
-
     if (!query['openid.claimed_id']) {
       const redirectURL = config.redirectURL || getRequestURL(event).href
+      const realm = url.port ? `${url.protocol}//${url.hostname}:${url.port}` : `${url.protocol}//${url.hostname}`
       const steamOpenIdParams = {
         'openid.ns': 'http://specs.openid.net/auth/2.0',
         'openid.mode': 'checkid_setup',
         'openid.return_to': redirectURL,
-        'openid.realm': `${url.protocol}//${url.hostname}`,
+        'openid.realm': realm,
         'openid.identity': 'http://specs.openid.net/auth/2.0/identifier_select',
         'openid.claimed_id': 'http://specs.openid.net/auth/2.0/identifier_select',
       }