To reproduce:

1. Navigate to "Dashboard" - "Manage Jenkins" - "Security" - "Manage Bitbucket Server consumers" - "Register new consumer".
2. Click the "Consumer key" field and type "bitbucket.example".
3. Then click the "Shared secret" field.

Expected behavior:

Either the form accepts "bitbucket.example" as the consumer key, or rejects it with a clear message such as "The consumer key must consist of alphanumeric characters and hyphens only".

Actual behavior:

The form displays "Consumer key cannot be empty", even though the consumer key is not empty.