Securty certificates often have an expiration date. The idea is that if bad guys eventually break the encryption, the expiration date will eventually cause them to be locked out again.
However, when certificates expire, this can cause problems for legitimate users – e.g., as when you try to access a https site that has an expired certificate, and get a security warning from your browser.
If this is a certfficate that you created, you might want to see something like
Edit, download, or delete provisioning profiles - Provisioning profiles - Account - Help - Apple Developer
If it is one that someone else created, you cannot "fix it." Only the person or organization who set up the expired certificate can.