The DST Root CA X3 is from Digital Signature Trust Co. and it is a root certificate included in Windows, macOS, etc. It was also used by letsencrypt.com a popular free TLS certificate provider. As a result many websites had to rotate certificates built upon this root certificate.
I would need more information about what certificate you are using based off this DST Root CA X3 certificate. If it's a website then the person that manages the site needs to rotate the TLS certificate with letsencrypt.com or if it's an application, etc. then you might need to install an update, etc.
Here's the expired certificate in my keychain: