While adding new widget this is showing.
Hello there, I hope you are doing well.
I notice that currently you have an STEM account, which allows you to have 1 dashboard to up to 10 widgets (you can check this information and more here).
Currently, we have an issue where when you try to add a widget above this limit, you obtain a page like the one from the image you shared. The team is working on fixing this as soon as possible.
Regards,
–Camilo