Error: "This request requires a user context"

I'm trying to initiate an outbound email using /api/v2/conversations/emails

But it says it requires a user context. I read on a thread that all conversations APIs require user context - is that correct? This particular usecase doesn't seem like a user-context situation where we initiate an outbound email to a queue.

If I am limited to user context, my follow-up question is this: if I'm calling a conversation API from a CRM that has implemented SSO, will it have user context? Or is there something more to be done?

Not all, but many. It's not documented so you'll only know when it does by getting an error message when you don't have a user context.

"SSO" isn't an OAuth grant type, but you can't use SSO with client credentials so presumably yes. Only client credentials don't have a user context.