Building ENV mongodb string with CA_CERT

I am very close to getting my mongodb database connected in the App Platform. I built up the env value like this

mongodb+srv://${db-mongodb.USERNAME}:${db-mongodb.PASSWORD}@${db-mongodb.HOSTNAME}/testing?authSource=admin&replicaSet=db-mongodb&tls=true&tlsCAFile=${db-mongodb.CA_CERT}

I get this error Error: ENOENT: no such file or directory, open ‘-----BEGIN CERTIFICATE-----’ which makes me think there is another thing like tlsCAFile but to point to a string instead, as the App Platform is giving me this CA_CERT through the ENV. I think it will work once I get this.

Thanks