Nationwide: High rates of 500 errors on calls to /transactions endpoint

Hi,

We're seeing a very high rate of 500 errors when we call the /transactions endpoint to retrieve transaction data for Nationwide accounts. This issue is widespread among our users.

Here's an example. Our request:

GET /open-banking/v3.1/aisp/accounts/OyfiZIZeSaXrtcnkpDlwq1JIQteROdKkNn8O4Z58/transactions?fromBookingDateTime=2018-05-18T00%3A00%3A00&toBookingDateTime=2018-11-18T23%3A59%3A59 HTTP/1.1
Authorization: Bearer ZNIC3TFwXo0tc1QACpqf7yhWdGzs
x-fapi-financial-id: 0015800000jf8aKAAQ
cookie: TS017d9441=0173a376556184ec2cd8f4acd210f6f56fa8acb7088f5adc44babd3d95f006605806b4ed5b1474c4fca7061c4d24fc4235506bc6f6
accept: application/json

Response:

HTTP/1.1 500
date: Sun, 17 Nov 2019 23:35:57 GMT
content-type: application/json
connection: keep-alive
set-cookie: TS017d9441=0173a376556184ec2cd8f4acd210f6f56fa8acb7088f5adc44babd3d95f006605806b4ed5b1474c4fca7061c4d24fc4235506bc6f6; Path=/; Domain=.api.nationwide.co.uk
transfer-encoding: chunked

{
"Code": "500",
"Id": "29c2fa23-818f-4fe1-9a1f-92c00389a55c",
"Message": "An error has occurred. Please see the details in the 'Errors' array for further detail",
"Errors": [{
"ErrorCode": "UK.OBIE.UnExpectedError",
"Message": "An unexpected error within the system has been identified. Please try again and if you continue to receive this error contact Nationwide for further assistance.",
"Url": "https://www.openbanking.org.uk/"
}]
}

Could you please look into what is causing these errors? I'm happy to provide additional examples if needed.

Thank you!
Nicole
Plaid team