This may occur if the HTTP probe configured incorrectly and has error in URL field.
Here are the steps to resolve.
- Log into UltraDNS
- Click on Domains
- Click on <domain name> containing sitebacker pool
- Click on the <sitebacker pool>
- Click Edit button of <HTTP probe> in Probes section
- Click Edit button in Probe Transactions section
- Fix entry in URL: field
- Click VALIDATE URL
- Ensure UI returns URL is validated
- Click DONE
- Click SAVE