PowerBI DatasourceError - Severe error occurred resolution help

[Uniqueusername]

Hi,

I keep running into this error (in the screenshot)  and I am not sure what is causing it

I have a composite datamodel with a mix of tables in Import and DQ mode connect to an SQL database. The model contains an Aggregated table ( created in SQL using a view).

The only way I fix it is when manually refresh the model which takes ages. But it does not explain why the problem pops up frequently everytime I re-open the pbix file

Anybody encountered this issue  ? How do you resolve it ?

[Uniqueusername]

apologies for bumping this for more visibility. This is really driving me nuts

[Uniqueusername]

Just an update on this.  My query transformations are done at the source.So there is nothing overly complex. Some my queries, used to create dimension tables are done here ( I have removed the settings only for the image)

The queries are very simple like

Seelct distinct column
FROm table_Name

And the results are about 4-5 rows. These are using import mode

EDIT : When I click on Refresh preview the tables load as they should. But when I click on refresh all that's when it breaks

[Anonymous]

Hi, @Uniqueusername 

According to your description, the data source error message occurs with mixed mode pbix files, you can try the following methods to solve the problem:

1. Ensure that the SQL database connection is properly configured and that the credentials are up to date. Check that SQL Server is accessible and responsive. Sometimes, network problems or server downtime may cause the error.
2. Make sure the data types and column names are consistent between the Power BI model and the SQL database.
3. Upgrade your version of Power BI Desktop.

Best Regards,
Yang
Community Support Team

If there is any post helps, then please consider Accept it as the solution to help the other members find it more quickly.
If I misunderstand your needs or you still have problems on it, please feel free to let us know. Thanks a lot!

How to get your questions answered quickly --  How to provide sample data in the Power BI Forum

[Uniqueusername]

Yes, I did check for all of that. I have not made any changes to names of the column

When I force a refresh it seems to work. That error seems to occur only when I re-open the file. There are no transformations on the source whatsoever - just two steps, Source and Navigation

The query refresh does take a very long time though. Not sure if that has anything to do with, like the servre calls getting timed out