EIK (Epic Online Services Integration Kit) is a plugin that enables seamless integration between Epic Online Services (EOS) and Unreal Engine. The plugin provides access to the EOS SDK (Software Development Kit) within Unreal Engine, allowing developers to easily implement features such as matchmaking, achievements, leaderboards, and more.
When clicking join from overlay, or invite and accept from overlay, both server and client output the following errors:
https://eoshelp.epicgames.com/s/question/0D5QP000005PMST0A4/unable-to-accept-invite-through-epic-overlay-due-to-error-is-not-a-valid-product-user-id?language=en_US
There appears to be a known bug in the eos SDK but rolling back to 1.15 results in the same thing.