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Regular Visitor

Data source error: We're sorry, an error occurred during evaluation.

We have used the Power BI desktop to create a report. The report data source is an external API which requires basic authentication. We have no problem refreshing the data in the Power BI desktop application.


However, when we publish the Dataset and try and to refresh the data in the Power BI (web version) we recieve the follow error.

Data source type:
Data source error: We're sorry, an error occurred during evaluation.
Cluster URI:
Activity ID: 653d7ecf-b95b-4105-9c56-48bf924b65ba
Request ID: ec081686-aa7b-d995-95ad-d7615ab97687
Time: 2016-04-29 01:01:38Z


We have reentered the Data Source credentials to ensure that is not the issue.


Thank you in advance for your assistance.



Frequent Visitor

Hi, I was wondering if you could elaborate on the solution for this problem.


I having the exact same error occur and I have tried wrapping the Web.Content in Binary.Buffer as suggested and am still getting the same error occur.



That sounds like a different issue, we need someone else's input on that, sorry 😕



Frequent Visitor

i am getting this error when i am trying to refresh the access db dataset using personal gateway. I have installed both 32bit and 64 bit redistributble engine for MS access

can anyone please help?

Community Champion
Community Champion

@gstuart which connector under Get Data have you used in powerbi desktop ?

I used the Web connector.


Web.Page doesn't apply Basic Authentication (because of security reasons we've disabled it). But, you can use it in Web.Contents.


Your query is probably shaped like this: Web.Page( Web.Contents( ...) )

Try adding Table.Buffer in the between:

Web.Page( Table.Buffer( Web.Contents( ...) ) )

Regular Visitor

Hi @arify,


Thank you for your prompt response.


I'm actually using Source = Json.Document(Web.Contents(...)). I took you advice and placed the basic authentication header into  Web.Contents and set Authentication type as anonymous so the basic authentication in the Web.Contents would be used.


Source = Json.Document(Web.Contents("",[Headers=[#"Authorization"="Basic ZZZZZZZZZ", #"Accept-Encoding"="gzip"]]))


Once again everything works in Power BI Desktop but when we upload it to Power BI (Web) and try and set up a refresh we recieve the below error.


Data source type:
Data source error: The 'Authorization' header is only supported when connecting anonymously. These headers can be used with all authentication types: Accept, Accept-Charset, Accept-Encoding, Accept-Language, Cache-Control, If-Modified-Since, Prefer, Referer
Cluster URI:
Activity ID: 9515d921-45ea-4cc7-b2db-cfb35b71ba14
Request ID: 161b99b8-32b5-da4f-df49-2c505f9ec77a
Time: 2016-05-01 02:19:26Z


I did try to setup  the Authentication method in Power BI (Web) as anonymous but receieved the below error.


Activity ID: 9515d921-45ea-4cc7-b2db-cfb35b71ba14
Request ID: ef8f1d3c-4d9b-b6d0-470b-ad7c240eb7b8
Status code: 400
Time: Sun May 01 2016 13:14:54 GMT+1000 (AUS Eastern Standard Time)
Version: 13.0.1100.472
Cluster URI:
Details: The credentials provided for the Web source are invalid.


I did see that you mentioned Web.Page in you previous message but I did not think it was applicable to this example.Please let me know if I was incorrect.


Thank you in advance for your assistance.

Can you try not putting Authorization headers in the option record, instead entering credentials in the prompt? (Still with Table.Buffer in there)

Regular Visitor

Hi @arify,


Thank you for your response.


As you mentioned I have removed the Authorization headers and added the username and password for basic authrnication under the Data source credentials in Power BI (Web). These creditals are checked and accepted without error.



In your previous message you mentioned "Still with Table.Buffer". As I am using Json.Document(Web.Contents(...)) so I used List.Buffer instead as Table.Buffer created an error. Example below. If I have misunderstood your implementation of Table.Buffer please let me know.


Source = List.Buffer(Json.Document(Web.Contents("")))


Once again this works perfectly in the Power BI Desktop but when published to Power BI (Web) I am still getting the refresh error as before.


I have noticed that Microsoft has reported Power BI as Service degraded with the following message.


Current Status: Engineers investigated reports that workbooks published to Power BI via the "Connect" option are failing to refresh and determined that a code regression is causing the problem. Engineers are currently developing a solution to remediate impact. Once the solution has been developed, it will be tested to ensure it fixes the problem and subsequently deployed throughout the affected environment.


I'm wondering if this has been the problem all along.


Thank you in advance for your assistance.







Sorry, I should have said Binary.Buffer, not Table.Buffer. Other thing is, it needs to wrap Web.Contents.


Can you try Json.Document(Binary.Buffer(Web.Contents(""))) ?


Regular Visitor

Hi @arify,


Thank you for your response and clarification.


I have made your recommended change by adding Json.Document(Binary.Buffer(Web.Contents(""))) and it works perfectly in Power BI Desktop but as soon as we publish it and try and refresh the data we recieveing the same error.


Data source error: We're sorry, an error occurred during evaluation.
Cluster URI:
Activity ID: 0c126fbf-e5da-453c-9af0-99108bdf2c25
Request ID: 783eec27-6501-6e8d-764e-2eed06eea470
Time: 2016-05-04 04:49:27Z

When you say 'publish', do you mean Power BI Service? If that's the case (works in PBI desktop, but not in PBI Service) can you open a ticket on the PBI Service website?

Regular Visitor

Hi @arify,


Thank you for your response and yes when I mentioned "publish" I meant the Power BI Service.


I will follow your instructions and open a ticket on the PBI Service website. Thank you for all your assistance and I appreciate you time in helping me resolve this issue.

I'm glad I could help 🙂

 arify could you post solution for this problem please. We are expreincing the same issue. 

Hi @dstramilov, the solution is already in this thread 🙂


Basically, you need to wrap your Web.Contents call with Binary.Buffer like my example in that reply.

I was able to publish one queries, but if I add several queries to datasaet I am getting error.

In Desktop version it works perfectly. I am using Function to get AuthKEY and pass it to each queries to get data.

I found out that Function is not supported when we publish report & schedule refresh.  

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