The code that is currently throwing that error was placed in there to avoid confusion or mistakes when copying over HTTPS vhosts.
A more appropriate error might be… “Only 1 vhost per file is currently supported”
The client will attempt to split off the SSL vhosts as separate files, copying over the content and then including the additional TLS/HTTPS specific directives needed. If HTTPS was only selected for one of the vhosts. The file would need to be split, and the new file would require a different naming convention.
I haven’t yet addressed this complication. Hence the currently thrown error.
Deleting the second VirtualHost block in that file should have corrected the problem though. (Ideally the second virtual host would go in its own appropriately named file.) That error is only thrown when attempting to make an HTTPS vhost when the original vhost file contains multiple virtual hosts.
I am very surprised the error persisted. You don’t have any directories under sites-available, do you?