Automatic rule does not work in Automator on MAC. Where to look for the reason?

Question

macOS

The task is to reduce the size of PDF files.
The program automatically uploads pdf files to the Dropbox folder. I create a folder action in automator. I specify the target folder where the files are added. I add a rule to look only for new files in this folder and process it with a filter to reduce the file size.
If new files appear in the target folder, then nothing happens. Not now, not at any other time. If you start the task manually, then all files are processed, everything is ok.
I've already rummaged through everything that is possible, activated the rule, deactivated it, even rebooted the poppy just in case :) nothing changes.