backgrounder.messages.datasource_wdc_increment_not_allowed when trying to refresh a WDC extract manually (errorCode=60007)

Hi!

I have created a web data connector on the Tableau desktop app, published it to my server and set it up to do incremental extract refresh once a day.

I added the WDC to the safe WDC lists and I have verified that DWC refresh is enabled in the server.

However, when I trigger the extract manually, I get the error:

This job failed on Nov 25, 2020, 2:52 PM after running for 0.0 min because of: Error incrementing extracts for Datasource: 'Uniper Events Data NEW'; backgrounder.messages.datasource_wdc_increment_not_allowed (errorCode=60007) 

I'm using Tableau Server Version: 2020.2.6 (20202.20.0913.2109) 64-bit Linux, running on Ubuntu 16.04.6 LTS.

My desktop version is 2020.2.7 (20202.20.1020.1112) 64-bit on a Windows 10 computer

I can't find any mention of this error or how to solve it anywhere.

Can anyone please help me resolve this?

Thanks,

Ilan