I followed this tutorial to setup HTTPS on AWS Ubuntu LAMP. I needed it to create Facebook canvas app. When ever someone else tries to load that app they get Failed to load resource: net::ERR_INSECURE_RESPONSE error.
Apeearantly Chrome and Edge don't deem my certificate trustworthy. Why is it? Can it be because I misspelled some info or do certificates have to issued by a thrid party?
You have created a self-signed certificate. It hasn't been signed by anyone in the chain of trust that ends up with the organisations that have certificates embedded into the browser or OS.
This is covered in detail in Step 5 of the tutorial you linked to.
do certificates have to issued by a thrid party?
Either that or the user must explicitly mark the certificate as safe.