After deploying my mern-stack app on cyclic, the page wants still to access localhost

Hello everyone, has someone experience with cyclic? I deployed my portfolio App there and all works fine, but I have no database access. So the page is empty. In the devtools of my page I have seen that it wants still to access localhost although in all my http-requests I have a dynamic path: ${window.location.origin}/api/soandso/. The logs on cyclic tell me, the server is running on port undefined. There is also said, that there is a problem with connection to the mongodb cluster. But I checked Mongo and there seems all to be good? Has someone faced this problem before? Best Roman

It might be helpful to provide a link to GitHub (containing the code) and a link to the deployed version of the project so others can easily help.

Thanks for your response: Roman-e-prog/portfolioApp (github.com) Thats the app: Portfolio Seite Roman Armin Rostock (cyclic.app) I changed in the meantime the path to a hardcoded one to my subdomain on cyclic but it helps nothing.

Ps. The port is now running on 5000 like it should. But there is no response