Intermittent 404 RESOURCE-NOT-FOUND error when provisioning

Hi,

I am trying to create a subscriptio/provision a new key pair to get started with the API but continue to encounter a 404 error when sending the POSTrequest.  The authorisation request appears to be working without issue, but I cannot get a number provisioned.  I have encountered this issue in the past, which then resolved itself without my input.  I cannot get a Get Subscription request to return a result for existing key pairs either - this also returns a 404 RESOURCE-NOT-FOUND error.  I have been through the documentation countless times, and cannot see anythign wrong with my requests, and am left thinking it must be an issue on your side?  If you can shed any light on the issue for me I would greatly appreciate the assistance.

Thank you

Helen