Environment File and API storage in Shinyapps.io

Hey guys
im super confused about an error I get, when trying to access my app on shiny apps with a second user .
The problem is, I don't know how to safe a R environment on the shiny apps server. I have to store a needed api-key in the app itself and due to install/overwrite it crashes for the other user or doesn't work at all.

I get the error with install = TRUE for the API-Key and readRenviron("~/.Renviron") to store the key for later sessions:
"Can't read/find the Environment file."

When I change it to overwrite = TRUE, the app works but just for one person and the app has to be manually restarted every time by me because:
"The APi-Key already exists" and the app crashes, when trying to access it via another computer.

I looked trough many posts but couldn't really find a simple answer to my question.

best regards,