**Steps to replicate the issue** (include links if applicable):
* Run the request in the code below
```
import requests
prod_url = 'https://wikimedia.org/api/rest_v1/metrics/unique-devices/en.wikipedia/all-sites/monthly/@20210501/@20210601'
header = {"accept": "application/json",
"user-agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36"}
response = requests.get(prod_url, headers=header)
print(f"The response status code is: {response.status_code}")
print(response.json())
```
**What happens?**:
the detail key in the error reponse returns a string stype
**local AQS 2.0 response:**
// invalid start date//
```
{
"detail":"start timestamp is invalid, must be a valid date in YYYYMMDD format",
"method":"get",
"status":400,
"title":"Bad Request",
"type":"about:blank",
"uri":"/metrics/unique-devices/en.wikipedia/all-sites/monthly/@20210501/20210601"
}
```
//invalid end date://
```
{
"detail":"end timestamp is invalid, must be a valid date in YYYYMMDD format",
"method":"get",
"status":400,
"title":"Bad Request",
"type":"about:blank",
"uri":"/metrics/unique-devices/en.wikipedia/all-sites/monthly/20210501/@20210601"
}
```
//both://
```
{'{
"detail': '":"start timestamp is invalid, must be a valid date in YYYYMMDD format', 'method': 'get', 'status': 400, 'title': 'Bad Request', 'type': 'about:blank', 'uri': '/metrics/unique-devices/en.wikipedia/all-sites/monthly/@20210501/@20210601'",
"method":"get",
"status":400,
"title":"Bad Request",
"type":"about:blank",
"uri":"/metrics/unique-devices/en.wikipedia/all-sites/monthly/@20210501/@20210601"
}
```
**What should have happened instead?**:
the detail key in the error reponse should return a list type
**prod response **:
//invalid start date//
```
{
"type":"https://mediawiki.org/wiki/HyperSwitch/errors/invalid_request",
"method":"get",
"detail":[
"start timestamp is invalid, must be a valid date in YYYYMMDD format"
],
"uri":"/analytics.wikimedia.org/v1/unique-devices/en.wikipedia/all-sites/monthly/%4020210501/20210601"
}
```
//invalid end date//
```
{
"type":"https://mediawiki.org/wiki/HyperSwitch/errors/invalid_request",
"method":"get",
"detail":[
"end timestamp is invalid, must be a valid date in YYYYMMDD format"
],
"uri":"/analytics.wikimedia.org/v1/unique-devices/en.wikipedia/all-sites/monthly/20210501/%4020210601"
}
```
**Software version** (skip for WMF-hosted wikis like Wikipedia):
N/A. All API based
//both://
```
{
"type":"https://mediawiki.org/wiki/HyperSwitch/errors/invalid_request",
"method":"get",
"detail":[
"start timestamp is invalid, must be a valid date in YYYYMMDD format",
"end timestamp is invalid, must be a valid date in YYYYMMDD format"
],
"uri":"/analytics.wikimedia.org/v1/unique-devices/en.wikipedia/all-sites/monthly/%4020210501/%4020210601"
}
```