AAD Client credentials error: AADSTS500031

Hi everyone,

I have five application registrations in an Azure Active Directory instance. One of the applications, created last month, allows me to create access tokens via the token endpoint using the client-id/secret as expected. The other four applications created this week have been setup in exactly the same way and aside from differences in IDs have identical manifest definitions however when I attempt to obtain an access token I am getting the following error:

{
"error": "invalid_request",
"error_description": "AADSTS500031: Cannot find signing certificate configured.\r\nTrace ID: 8939a6d0-c08d-4a5c-b6c6-be1b9ca69f00\r\nCorrelation ID: 2622dd04-5eb9-4e84-b217-840a4d9c6eba\r\nTimestamp: 2020-11-04 09:43:16Z",
"error_codes": [
500031
],
"timestamp": "2020-11-04 09:43:16Z",
"trace_id": "8939a6d0-c08d-4a5c-b6c6-be1b9ca69f00",
"correlation_id": "2622dd04-5eb9-4e84-b217-840a4d9c6eba"
}