You're on Johnny. Johnny does not have Autossl, so it does not provide ssl certificates for you. You need to manually generate and install a new certificate using a service like zerossl to fix this problem. Your current one is expired. Free certificates are usually only good for 90 days, so you need to install a new one a few times a year to keep this warning from appearing. Alternately, you can move to either of our other servers to fix this. Ricky and tommy provide certificates for you through autoSSL.