Solution:

• Check DNS settings: Verify that the A records or wildcard subdomain entries are properly configured in your Zone Editor.
• Check for DNS propagation: If you recently updated DNS settings, allow time for them to propagate.
• Check subdomain limits: Some hosting plans have limits on the number of subdomains you can create. Contact your provider to check your current quota.
• Clear browser cache: Sometimes, a caching issue in your browser can prevent subdomains from being created. Try clearing your cache or using a different browser.