NFT Game, Windows App (Metamask Login Error) — 4

I have hired 3 guys to do to me the NFT project, and im working on it since 4 months.
I totally completed the work of the NFT design and im ready to publish my website.

I hired also a freelancer to create to me the NFT game app, but it makes to me a lot of errors and when i click ‘login with metamask’ it makes to me an error that the app has been closed.

I dont know why the app it make a problem, so i have paid him 700$ as a down payment, and i will complete to him the other amount when he complete the full app.

So i still waited 2 weeks, and he back’s to me with an answer, sorry the problem is so complicated and i cannot resolve the problem.

I didn’t ask him to return the money to me because he did his job and deserved it. But the bad thing is that he did fix the problem, which was done by him, not me.

So im now here to hire someone very professional, to fix to me the problem while login via metamask, due the problem i think its easy, if he click login via metamask i see this problem ” The app has been stopped” , so i wanna fix this problem.
– i want the user when he click login via metamask, he will be redirected to connect her wallet to start discovering the NFTS. And i will pay you if you fix this problem for me. Because i will launch my project next month .

Please anyone who is beginer, i respect you but dont bid on my project if you are unable to fix the problem.
Thanks.