planner access issue - external tenant?

Solution Option for External Tenant Access to Planner

Please follow below steps 

1. Use Microsoft Teams for Cross Tenant Collaboration

Planner integrates with Microsoft Teams, which allows limited collaboration with external users through guest access

Steps

1- Add the external user as a guest in your Microsoft 365 tenant

Go to Azure Active Directory Admin Center > Users >New Guest User.

Invite the external user via their email address.

2- Create a Microsoft Teams team and add the external user as a guest.

3- Add a Planner tab to the team

External users can view and update tasks in the Planner tab within Teams.

Note External users cannot directly access Planner from the Planner app they must interact with it through Teams.