I am having an issue where the self signed continues to be presented even though I have loaded my own certificate, set it to default and even deleted the old self signed certificate. I checked the files in /etc/asterisk/keys/integration/ and they are updated with my certificate.
Where do you see it being used? If HTTPS, make sure that you have it set properly in System Admin > HTTPS setup
I did set it up in the System Admin > HTTPS Setup section and its listed under Apache configured box with the date my cert expires in 2 years
Modern browsers will only consider certificates valid if their validity period is 13 months or less. Any certificate that has a validity period longer than 13 months is considered invalid.
These standards changed in 2020.