This certificate has an invalid issuer : Keychain marks all certificates as "Invalid Issuer" [duplicate]
In Keychain access, -> View -> Show Expired Certificates, then in your login keychain click on expired certificate and delete it. I also had the same expired certificate in my System keychain, so I deleted it from there too.
-> After deleting the expired cert from the login and System keychains,download certificate from below link and open with keychain.
Download https://developer.apple.com/certificationauthority/AppleWWDRCA.cer and add it to Keychain access > certificates (which expires on 2023)