This error is seen when you open the Veeam Backup and Replication console “Failed to check certificate expiration date”
Its seems like there is a bug in Veeam Backup and Replication that hits you 11 month after you install or upgrade to 9.5 U3 – luckily Veeam is already aware of it and some helpful URLs has been revealed in Anton Gostev weekly newsletter that can assist in solving this error: