JunOS : Upgrade return ERROR: Package signature validation failed. Aborting install.

Experiencing the following error while upgrading JunOS?

Verify the signature of the new package
verify-sig: cannot validate certs.pem
certificate is not yet valid: /C=US/ST=CA/L=Sunnyvale/O=Juniper Networks/OU=Juniper CA/CN=PackageProductionRSA_2018/emailAddress=ca@juniper.net

ERROR: Package signature validation failed. Aborting install.

This error could be caused by incorrect date and time set on your device (back in time).

To validate the current value, enter in shell mode and issue the “date” command.

Example :

root@:RE:0% date
Wed Jan 20 09:19:48 UTC 2016"

To set the date and time, use the command “date YYYMMDDHH.MM” (Year | Month | Day | Hour | Minute)

Example :

root@:RE:0% date 201809130608.00
date: connect: Can't assign requested address
Thu Sep 13 06:08:00 UTC 2018

Then go back in “cli” mode and attempt the upgrade again

root@:RE:0% cli

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