the same thing started to happen to us since friday. outbound calls that have been going seamlessly for months and months on same system with less than 4% getting vonage-rejected error now can be 100% of all errors that are not failed to connect, or customer-did-not-answer then suddenly it works for 20 min, then goes away again..
9ffa7588-f501-468c-835b-90a315c5bee9, b835c64c-8b5b-49ce-bea7-9db0cdb37d62, 7eec09bf-5bdf-4e52-b95a-084537d7bb93, 1612a088-6dec-4cd3-9a2d-041d17ff5a74, e7bf9eb7-5d8c-474e-b375-918ae3bd8743, 3728c1f2-15b8-44be-9faf-d09445ee87b6
hope this helps.