Unable to find a team

Hi guys.
I'm pretty new at this, and have a problem I really need help with.


I hired a developer to create an app from scratch for me, since it was to complex for me to do myself.

I got the sourcecode, and it all works fine when i run it on xCode simulator, but as soon as I try to run it with my iPhone as target, i get 2 errors.


1: "Failed to code sign in "App name"

No valid signing identities (i.e. certificate and private key pair) matching the team ID “TeamID-that is propably the developers” were found.



Xcode can attempt to fix this issue."


I press Fix Issue and then I get prompted with the second error.


2: "Unable to find a team with the given Team ID 'TeamID-that is propably the developers to which you belong. Please contact Apple Developer Program Support.

https://developer.apple.com/support"


I've used over seas developers before, and downloaded sourcecodes from internet, but never had this problem before.
Any ideas on how to fix this issue?


Thanks