DataSource.Error : Web.Contents failed to get contents from « https://XXXXXXXXX » (500)

Hi Anonymous,

I suggest that you first test the availability of the API directly using one of the other tools. For example, postman. Make sure the headers information is correct. It may be that some of your headers are missing, such as connect-type or User-Agent.

500 statu code is mostly the server encountered an unexpected condition that prevented it from fulfilling the request.

500 Internal Server Error - HTTP | MDN (mozilla.org)

Best Regards

Community Support Team _ chenwu zhu

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

I even expirienced this when my authentication header was not in the right order. 

It is always adviced to contact the support team of the API you are trying to connect. 

Secondly first try to connect to the api using Postman, if that works you know you have the right header and possible body in place

good example of a platform that takes care and delivers support on their API is mediavalet. You can refer to your api supplier to their website to show how good api documentation looks like. They also deliver an app collection for postman so you know exactly how the api should work. 
MediaValet API

now for that specific solution this is the way to go: 
I expirenced that if you do this the application/json content type is changed to application/x-www-form-urlencoded by power bi

let
TokenReq = Web.Contents("https://login.mediavalet.com/connect/token", [
Headers = [
#"Content-Type" = "application/x-www-form-urlencoded",
Authorization = Base64cred
],
Content = Text.ToBinary("grant_type=password&username="& Usr & "&password=" & Passw & "&scope=api")
]),
TokenJson = Json.Document(TokenReq),
Token = TokenJson[access_token],
Token2 = Token,
SearchReq = Web.Contents("https://api.mediavalet.com", [
RelativePath = "assets/search",
Headers = [
#"Ocp-Apim-Subscription-Key"= SubscriptionKey,
#"Content-Type" = "application/x-www-form-urlencoded",
Authorization = "Bearer " & Token
],
Content = Json.FromValue([
search = "PietjePuk",
count = 1,
offset = 0,
sort = "record.createdAt D",
searchFields = "attributes",
includeSoftDeleted = true,
filters = "DateUploaded GE 2025-02-22T01:55:39.496Z"
])
]),
Jsonresult = Json.Document(SearchReq)

in
Jsonresult

I know this has been marked as solved but what worked for me was simply removing the percentage from the Sharepoint File's name

I double clicked on the Source query step in power query and changed the view mode to Default instead of All. That fixed it.
My issue was with a sharepoint list.