Timeout

The connection either timed out or was lost

Power BI dataset refresh error: what it means and how to fix it.

What this means

The Analysis Services / semantic-model connector lost the connection (transient network, or a complex M outer-join stalls).

How to fix it

  1. Retry the refresh.
  2. Table.Buffer the outer-join table to stabilize the join.
  3. Simplify the joins.
View on Microsoft Learn

Frequently asked questions

What does the "The connection either timed out or was lost" error mean?
The Analysis Services / semantic-model connector lost the connection (transient network, or a complex M outer-join stalls).
How do I fix it?
Retry the refresh. Table.Buffer the outer-join table to stabilize the join. Simplify the joins.
Where does this Power BI refresh error appear?
It appears in a Power BI semantic model's refresh history when a scheduled or on-demand refresh fails.

Catch this automatically

RefreshRadar monitors every Power BI dataset refresh and emails you when one fails, with the likely cause and the fix, so you are not hearing about a broken refresh from your stakeholders first.