I have done a web app and installed on VPS frontend and backend together. The frontend is on domain and the backend is on subdomain. I have a problem with connection between them, i get this error:

I have done a web app and installed on VPS frontend and backend together. The frontend is on domain and the backend is on subdomain. I have a problem with connection between them, i get this error:

I have done a web app and installed on VPS frontend and backend together. The frontend is on domain and the backend is on subdomain. I have a problem with connection between them, i get this error: