I'm sure many other have had customers reporting this error:
Stripe doesn't currently support application fees for platforms in US with connected accounts in **.
This seem to happen if you are opting for Direct Payment and are from certain countries (Brazil in my case).
My Stripe account is already configured to receive international payments, so I don't know what else can I do on my side. For what I've read elsewhere this is a problem with transaction fees being charged by the platform, so perhaps someone from itch.io's support can help me out? Thanks!