In some cases, the Floating License Server (FLS) can show 1970 as the license end date.
This is linked to having an older version of the FLS, and can be solved as follows:
1. The License server software (for both Local and/or Floating licenses) has not been updated to V7.x
Solution: Upgrade your Local/Floating License Server to V7.x
2. The licenses are not reactivated with the new License Server software V7.x
Solution: After upgrading the License Server software to V7.x, reactivate the licenses through instant activation or by registering of a .matkey license file from https://passwords.materialise.com