Daily PowerBI refresh fails in most of the cases

Hello, community,

I use daily data refreshes between Simplicate and PowerBI. (Odata)
The data in PowerBI service are stored in several datamarts in a PowerBi Premium workspace.
In the last few days the refreshes failed almost every time (90% of the cases) .

In the PowerBI log I can see a general error message:

Refresh start time,Refresh end time,Refresh Status,CPU Usage (milliseconds),Table start time,Table End Time,Dataflow table name,Partition name,Rows processed,Error
00:00:00,00:00:00,Not Found,Error: undefinedErrorMessage=The current operation was canceled because one or more operations failed…HttpStatusCode=0.

However, I tried to find the transaction in bridge online monitoring. (https://bridge-online.cloud/monitoring). Here I can find the transactions, and a more detailed error message:

“The data download was canceled after 4 seconds, such as by the user navigating away in the Power BI or Power Query user interface. (/*****.simplicate/odata4/Simplicate.CRM.OptionOrganizationCustomFields@spe).”

I have no idea what can be the problem. I do not navigate away, however, for refreshes it is allowed to close the browser, where you started. It can not be a problem. Somehow powerBi closes the connection?
Can someone help? how can I go deeper in analyzing the problem?

I did not find any solution in the community for my problem.

Thank you for all your support.