diff --git a/keyserver/src/user/login.js b/keyserver/src/user/login.js
--- a/keyserver/src/user/login.js
+++ b/keyserver/src/user/login.js
@@ -146,6 +146,14 @@
       return identity_info;
     } catch (err) {
       console.warn('Failed to register user: ' + getMessageForException(err));
+      if (userInfo.usingIdentityCredentials) {
+        console.warn(
+          'Please re-enter `nix develop` and provide new user credentials' +
+            '\nFor keyservers running in Docker, set different ' +
+            'user credentials in COMM_JSONCONFIG_secrets_user_credentials, ' +
+            'remove all tables from the database, and restart',
+        );
+      }
       throw new ServerError('identity_auth_failed');
     }
   }