We didn't make any changes on the backend.
While setting up your workflow, in the 'Search Contact by Email' action step, ensure you search for a contact that already exists in your Systeme.io account. This will provide you with the Contact ID, which you can then use in the Filter step. If you search for a contact that doesn't already exist in your Systeme.io account, the response will be '0', and you won't be able to set up the Filter step.
All we did was add the contact with the provided email address to your Systeme.io account, which gave us a Contact ID that we then used in setting up the Filter conditions.
View attachment 47200