Gateway looses connection to SQL Server w/o a recognizable pattern

[KilianG]

Hi every one!

In a PowerBI reporting hosted in a Pipeline in the PBI Service, we're using data from onPrem SQL DBs via a onPrem gateway.
The problem:

In the last time our reports cannot refresh and we get a "DM_GWPipeline_Gateway_MashupDataAccessError" error.
The strange thing is, that this happens only mostly - means a few times a refresh is possible, but nearly everytime it fails.

• One behavior: we test the connections in the Gateway and they are validated or set to offline without a recognizable pattern, within minutes.
• Or: while having validated connections (showing "online") in the Gateway, at the same time a refresh of the data/semantic model is rejected from the service, claiming "Microsoft SQL: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible."

We already checked the gateway - it has all needed rights and all needed ports are opened (confirmed by the gateways diagnostics)

But anyway, we made no changes to the gateway,. Further more we can exclude errors in the report itself, since this behavior is reproducible with old versions of the reporting too.

Does anyone has a clue how to fix this issue?

[KilianG]

i was able to connect to the datasources via cloud connections - this solved the problem on firstsight.

But now i have another problem:
Now it's not possible to remove the gateway connections. Although all datasources have a working cloud connection the powerbi service still says a gateway is needed. If i map all datasources to the cloud connectors in the semantic models settings, i'm not able to save my changes (the save button is greyed out).
Does anyone habne a clue how to solve that?

[lbendlin]

How many gateway cluster members? Are they all configured the same? Can you reach the database from each VM?

[KilianG]

Only one Cluster member (so it is no configuration issue, i guess) and yes - i can reach the DB from the VM.