You may experience problems accessing the Chargify API via a client that does not have updated trusted root certificates.
Chargify is in the process of attempting to replace an intermediate certificate which may, for some clients, force them to use a more recent (and unexpired) root that they already trust.
In the meantime, Chargify merchants can fix this for themselves by adding more recent root certificates to their trust stores. Add either one of these to the certificate store used by your client:https://crt.sh/?id=1199354https://crt.sh/?id=1720081
Note the "Download Certificate: PEM" link on the above webpages to obtain the certificate.
For example, if you are using curl as your client, you can specify a certificate authority file to use:
curl --cacert /etc/ssl/1199354.crt -u API_KEY:X https://subdomain.chargify.com/subscriptions.json
The above is an example. How to install or use the updated certificate is dependent on your client.
You can learn more here: https://support.sectigo.com/Com_KnowledgeDetailPage?Id=kA03l00000117LT