When trust centers switch to a new PKI infrastructure, it can happen that signatures that were created with very new signature cards are not validly validated. This is due to the fact that the new Trusted Lists (TSL) and / or Root CAs were not yet implemented at the time our software was released.
The Update of the trust lists in Sign Live! CC these signatures are validated again.
Via menu item Tools> Certificates> Update Trust Lists trigger the update of the trust lists manually.