Which certificate condition is NOT a requirement for Mimecast support to provide relaxed encryption?

The condition that does not represent a requirement for Mimecast support to provide relaxed encryption is having a valid certificate authority. Relaxed encryption typically applies in scenarios where specific encryption limitations might be bypassed based on specific conditions of the certificate being used.

Certificates that meet certain criteria, such as having a key length of less than 1024 bits, being self-signed, or being expired, may influence the type of encryption support provided. These conditions are associated with security standards and practices that Mimecast may use to determine the appropriateness of relaxed encryption for certain certificates.

On the other hand, having a valid certificate authority is fundamental for ensuring the trustworthiness and security of the communication channel. A well-established certificate authority (CA) helps establish the identity of parties in the communications, which is necessary for secure encryption practices. Hence, while relaxed encryption may be possible in certain cases, it is not dependent on the presence of a valid CA, making it the correct choice in this context.