Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. https://crt.sh/?q=example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
A picture paints a thousand words.. but there is no picture (showing the problem).
Words count as words, but there are no words used to describe... (the actual problem).
Other than:
So I am left to guess.
...
I think you may be using WWW and your cert doesn't cover the WWW name.
I don't have the time to go through the video, but I would guess that wherever you used the single domain ("backwardsla.com"), you would use both names ("backwardsla.com" and "www.backwardsla.com").
This should be able to be done right over the existing one (not 100% certain - again, I haven't watched the video)
You’re going to make me have to read…
What was the command you ran?
It looks like: ./letsencrypt-auto --apache -d fever.lookahead.io
That example needs to be augmented to cover your case: ./letsencrypt-auto --apache -d backwardsla.com -d www.backwardsla.com
Now I have some Archaeological “work” to get back to.