Heatmap URL regexp not working

The part of my URL will always be dynamic - containing multiple capital letters - like so: ASDFG. I am trying to get the dynamic part of the URL to work with heatmaps via regexp, like so

It seems to be a valid regex based on the regex validator - https://regexr.com.

Also verified the regex with this regex validator.

What am I doing wrong?

Hi there,

You don’t need to escape any characters, please see below: