Created amazon connected instance, but not able to claim atleast one phone number

From what is shown in documentation this is a known issue that requires a support case.

In documentation it shows under Connect Quotas- Phone numbers per instance: 5 Under Default value there is a note that says - It's possible to get an error message that "You've reached the limit of Phone Numbers," even if it's the first time you've claimed a phone number. All the issues that cause this error message require help from AWS Support to resolve.

I submitted a case in the Service Quotas Service. Hopefully it will be resolved shortly.