.NET Core Docker with Automated SSL
I figured it all out, the solution was luckily pretty simple. I don't know why, but Microsoft for some reason simply chose to format their environment wrong. To fix this, simply use = rather than : without the space:
(...)environment: - DB_HOST=db - VIRTUAL_HOST=my_domain.com - LETSENCRYPT_HOST=my_domain.com - LETSENCRYPT_EMAIL=my@email.com(...)