Data refresh takes too long

[fskhalasm]

Hello,

we have installed and running Power BI Report server for several month.

Actually running the very last version: Version 1.2.6690.34729 (March 2018).

We are facing with refresh issues.

Sometimes the scheduled refresh takes too long (more than hour) and crash on timeout:

"Message":"Timeout expired. The timeout period elapsed prior to completion of the operation.. The exception was raised by the IDbCommand interface.

On other times the same report it's running smoothly and data refresh takes about 20 seconds.

PBIX report on server has been not modified, the ammout of data to be refresh are the same and manual refresh in Power BI desktop do not takes longer that 30 seconds.

Any idea why the refresh of the data can have such kind of strange behaviour?

Thanks.

Marian

[MaheshDadhich]

I also have the same issue. My report is refreshed in few second when I refresh manually but takes 18 min when it is refreshed through schedule. 
did you get any solutions for it why does it happen and why is this difference