Using EU VIES REST Service to check VAT Number

So i'm trying to check VAT Numbers using the REST Service the EU provides.

Here is some documentation about it:
https://ec.europa.eu/taxation_customs/vies/#/technical-information

I'm using Postman for a check. Using this URL:
https://ec.europa.eu/taxation_customs/vies/rest-api/check-vat-test-service

The request body JSON example:

{
  "countryCode": "DE",
  "vatNumber": "DE129273398",
  "requesterMemberStateCode": "DE",
  "requesterNumber": "DE811115368",
  "traderName": "Bayerische Motoren Werke Aktiengesellschaft",
  "traderStreet": "Petuelring 130",
  "traderPostalCode": "80809",
  "traderCity": "München",
  "traderCompanyType": "AG"
}

I always (for over a week) get the answer the service is not available:

{
  "actionSucceed" : false,
  "errorWrappers" : [ {
    "error" : "SERVICE_UNAVAILABLE"
  } ]
}

When using this URL:
https://ec.europa.eu/taxation_customs/vies/rest-api/check-vat-number

with the same request body i always get:

{
    "countryCode": "DE",
    "vatNumber": "DE811115368",
    "requestDate": "2023-11-04T14:19:45.180Z",
    "valid": false,
    "requestIdentifier": "",
    "name": "---",
    "address": "---",
    "traderName": "---",
    "traderStreet": "---",
    "traderPostalCode": "---",
    "traderCity": "---",
    "traderCompanyType": "---",
    "traderNameMatch": "NOT_PROCESSED",
    "traderStreetMatch": "NOT_PROCESSED",
    "traderPostalCodeMatch": "NOT_PROCESSED",
    "traderCityMatch": "NOT_PROCESSED",
    "traderCompanyTypeMatch": "NOT_PROCESSED"
}

Am i doing something wrong?

Afaik detailed information on the holder is not available for German VAT numbers. If you omit the "DE" prefix from the fields vatNumber and requesterNumber, you will get a result for valid from https://ec.europa.eu/taxation_customs/vies/rest-api/check-vat-number though.

If you test with a Austrian VAT#, for example, you'll get more information.

{
  "countryCode": "AT",
  "vatNumber": "U18522105",
  "requesterMemberStateCode": "DE",
  "requesterNumber": "811115368"
}

results in

{
    "countryCode": "AT",
    "vatNumber": "U18522105",
    "requestDate": "2023-11-04T15:00:25.677Z",
    "valid": true,
    "requestIdentifier": "WAPIAAAAYua2Xl4O",
    "name": "KSR Group GmbH",
    "address": "Im Wirtschaftspark 15\nAT-3494 Gedersdorf",
    "traderName": "---",
    "traderStreet": "---",
    "traderPostalCode": "---",
    "traderCity": "---",
    "traderCompanyType": "---",
    "traderNameMatch": "NOT_PROCESSED",
    "traderStreetMatch": "NOT_PROCESSED",
    "traderPostalCodeMatch": "NOT_PROCESSED",
    "traderCityMatch": "NOT_PROCESSED",
    "traderCompanyTypeMatch": "NOT_PROCESSED"
}