Dataflow Gen2 Error - On-Premise Oracle Database

[MMD1]

Hi everyone! I am pulling data using Dataflow Gen2 for a customer from an on-premise Oracle database.

I know the gateway is working, as it is pulling data from some tables (smaller tables) into a lake and it's doing just fine.

On the other hand, when pulling data from larger tables (5m+ rows and less than 30 columns) the process fails. The flow is not doing any calculations, just pulling the data from the data source. What could be the reason for this? How can I trouble shoot it?

I've even tried to put the table in its own Dataflow to write into the lake, but it still fails. 

Not sure that it matters, but I should note that we are using Fabric in trial mode.