Slack Notification Fails because Root CA Certs Out of Date

[jonmchan]

Getting a curl: (60) SSL certificate problem: certificate has expired when trying to send the slack notification.

The Root CA Certs have expired and need to be updated.

The following commands work to fix the issue:

sed -i 's|^mozilla\/DST_Root_CA_X3\.crt|!mozilla/DST_Root_CA_X3.crt|' /etc/ca-certificates.conf
curl -sk https://letsencrypt.org/certs/isrgrootx1.pem -o /usr/local/share/ca-certificates/ISRG_Root_X1.crt
update-ca-certificates --fresh

The following errors/warnings may be produced, but they do not keep the issue from being resolved.

Warning! Cannot copy to bundle: /usr/share/ca-certificates/mozilla/AddTrust_External_Root.crt
Warning! Cannot copy to bundle: /usr/share/ca-certificates/mozilla/Certinomis_-_Root_CA.crt
Warning! Cannot copy to bundle: /usr/share/ca-certificates/mozilla/Certplus_Class_2_Primary_CA.crt
Warning! Cannot copy to bundle: /usr/share/ca-certificates/mozilla/Deutsche_Telekom_Root_CA_2.crt
Warning! Cannot copy to bundle: /usr/share/ca-certificates/mozilla/Swisscom_Root_CA_2.crt
Warning! Cannot copy to bundle: /usr/share/ca-certificates/mozilla/UTN_USERFirst_Email_Root_CA.crt
Warning! Cannot symlink /usr/share/ca-certificates/mozilla/ISRG_Root_X1.crt -> /etc/ssl/certs/ca-cert-ISRG_Root_X1.pem
WARNING: ca-certificates.crt does not contain exactly one certificate or CRL: skipping