S4B On prem users cannot message or call Teams only users

Hi there,

I am starting the migration of users from S4B on prem to Teams and i have noticed when i migrate a user to Teams only, their presence from a S4B user using the S4B client  is unknown.

Further the S4B user cannot call or message a Teams only user. Teams to Teams is fine.

Configured S4B in hybrid mode.

Default co existence is islands mode.

Looked through this document and it should work

https://docs.microsoft.com/en-us/microsoftteams/coexistence-chat-calls-presence

Thoughts?