I am dealing with Apple Developer Accounts every day and contact Apple Developer Support when needed. The Screenshot show that your iTunesConnect account is not yet active. Try to go into the Membership section and see if the creditcard has not expired and if the automatic renewal is active.
Now Apple is moving from iTunesConnect to AppStore Connect, but is now still accessible at the link itunesconnect.apple.com. The admin/owner of the developer account has to contact Apple Developer Support to ask Apple to activate your iTunesConnect account.
Also, another reason for your problem can be that the owner of the Developer Account has already signed up, but that it takes time to process by Apple. In some cases this goes wrong. Apple can solve it immediately after you have called them.
Another explanation is that you signed up, but that Apple still wants to verify your identity and has not received a reply from an e-mail they've sent to you (for example the question to provide a passport/government issued ID). Do as Apple requests to get iTunesConnect active. If it takes too long for you to reply, Apple will suspend the account, and the registration will be cancelled. The owner of the Developer Account will still have an AppleID, but cannot use Developer Account Resources such as iTunesConnect.
Note that a developer account is not free, but costs 99 dollars per year. Only after identification process and payment, iTunesConnect (or now AppStore Connect) becomes available.