I installed this app hoping I could offer my customers a complimentary gift with purchase during a seven day promotional period. After installing this app, I followed the instructions by first setting up the automatic discount (free gift) in Shopify, the next step is 'synchronization' which can take some time. Well I waited and waited (half an hour or so) and every time I clicked the refresh button it came with an error. I can see 'cache' is pending but I don't have time to sit around an await. For me, this app appears easy but it did not work. Onwards and upwards!
Sorry to hear that, indeed some users encounter this error but it is unfortunately not on my side. There is a resync issue on Shopify side. I usually send them an email with the name of the store and it's enough to resolve the problem.
EDIT: This issue has been fixed by the Shopify team, you can now try again