This seems like the user account doesn't have necessary permission/roles to access the specified project. I would recommend you to refer
this help center article where it explains the Identity and Access Management (IAM) roles that are required at the project level for accessing a project.
Refer the above mentioned documentation and check whether the user account have the right permissions/roles to access the project. If the user account account have the right roles/permission (for example :-
Owner), you might need to seek support either through
GCP's support channel or by creating a
Private issues using the
issue-tracker.
I hope this helps.
Note: While opening an issue-report or seek assistance through support channel, please include all necessary information (Ex:- reproduction steps, details of error reports along with screenshot etc) you have followed along with project details(Ex:- project number).