I think it would be best to contact support, since you cannot access the project and make any changes.
But before that you can do one thing, if you have custom codes applied from Dashboard, try removing it and see if that work. Or you can also restore from previous backup if you think you have not done much changes.
Thanks, all custom code was added in the designer and has been added a while ago. Never caused any problems before. Anyway I’ll contact support then. Thanks!