I am a member of my company's development team, with the role of Admin. I can access the Member Center of the team at https://developer.apple.com/
However, when I I attempt to sign in at https://itunesconnect.apple.com I am presented with the following error message:
Your Apple ID isn't enabled for iTunes Connect. Learn More
I am an admin on the development team. When I visit Developer > Member Center > People
I do not see any permissions related to iTunes Connect.
How do I gain access to my team's iTunes Connect portal?
It is not enough to be a member of the Apple Developer Account / Member Center team.
The account must also be added as an iTunes Connect User.
From an existing iTunes Connect admin account, add the new user to iTunes Connect:
iTunes Connect > Users and Roles > "+" > Add iTunes Connect User