When installed on Debian 10 the proftpd service will not start.
After debugging this it does not start because it is unable to read the keys from:
On Debian 10 the SSH keys are no longer the RSA/DSA format. Instead they are of this format:
-----BEGIN OPENSSH PRIVATE KEY-----
Proftpd is unable to read them so it fails to start.
A manual solution to this is to regenerate the 2 keys and specify rsa and dsa format is required.
Not sure how to report this to the Virtualmin team but hopefully they will read it.