If the client is trying to add you to their team they will need to send the invitation using your email address. If your client needs any help, you can refer them to reach out to us here or directly to Customer Support so that we can assist them further. Thank you.
Please share the contract ID or the client name along with the email address in the screenshot with me via PM (click on my name > send a message) so that I can check this further. Thank you.