datamart error- when adding custom column, credentials invalid error appears

[Lena85]

Hi,

I have a working datamart for several months now, which updates daily without failure.  I however encounter issues when trying to expand on it by adding additional columns. 

When I try to add custom column

( to do that custom column function used, and I was calculating a difference between two dates in days, no syntax errors detected and the result looks correct in preview of power query):

 to one of the tables within the datamart, and save, following error appears:

Activity ID: 7d5739da-8dba-4417-b392-20105d3513a6
Request ID: 4a443221-d734-48b2-a9b3-0a6d5312a4ee
Correlation ID: 71fd4b90-9232-f162-3d73-a391b91a1e63
Status code: 400
Time: Mon Jan 09 2023 14:54:54 GMT+0100 (Central European Standard Time)
Service version: 13.0.19635.59
Client version: 2212.1.11454-train
Cluster URI: https://wabi-west-europe-e-primary-redirect.analysis.windows.net/

When I press Return to Editing, I have the Power Query window with credentials error:

I press Reconfigure Connection to re-enter credentials, and re-enter the credentials but the error persists.

When I do to the settings of the datamart, I see that there also appears to be a credentials issue- however, if I try to Sign In, there is no window popping up to re-enter, instead, I get the following error. I tried in two different browsers. 

The strip under Authentication method is empty when opened. When 

This is really annoying and prohibitive in scalling up our datamart use. Does anyone have an idea of how to solve it and work around it? 

[Anonymous]

Hi @Lena85 ,

Sorry we couldn't reproduce your issue.
In our survey we found that there was a user who had a similar experience to you, who created a support ticket eventually concluding that it was a data type issue.

Please check whether the data type of your custom column is Any, and try changing the data type.
For more information, you can refer to. Datamart operation canceled - Microsoft Power BI Community

Best Regards,

Neeko Tang

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