XPS 15 9530, dock, issues with two external monitors

I have the laptop (XPS 15 9530) connected to a DELL Dock, and 2 monitors attached to the dock. I used to be able to connect the laptop power (keep laptop closed), and both monitors would show me the extended desktop and I could log in. Now, when I do that, only one monitor shows the desktop, and when I log in, the other monitor stays dark. When I open the display dialog, and tell the laptop to look for the other monitor, the response is that no other monitor can be found.

However, when I open the laptop, it's screen activates, and so does the second monitor, and it shows the extended desktop as before. When I close the lid again, the second monitor goes dark again, and my laptop cannot find it.

I suspect that a Windows 11 update broke this. I updated the laptop software and the dock firmware, but that did not change anything.

Has anybody seen that behavior, and if so, how can I correct that?

<Our users need to know which specific dock model and both monitor models. DELL-Admin>