Hi there Marho.
Confirming it was a fresh install of the latest version of all of your plugins (Event Calendar, Event Tickets etc).
I also have pretty permalinks setup.
Happy to follow a guide. We do have WooCommerce using a webhook for Stripe and MemberPress uses a stripe webhook – but these have been created/setup separately to avoid conflicts using the same webhooks.
Any suggestions appreciated ??
Best regards
Jacob