You work as a Systems Administrator for your company. The company has several departments including a Research and Development department.
The company has a subscription to Microsoft 365. All users in your company have a Microsoft 365 E5 license.
You have configured a Team for each of the departments.
The Research & Development team has a channel named Design. The company plans to work with an external contractor to help design a new product. You have created a guest account for the contractor.
The contractor reports that he is unable to post to the Design channel.
You need to enable the contractor to post to the Design channel.
Which of the following actions should you perform?