Can I register a licence in SMG some days before the start date?

Hi, I have four Symantec Messaging Gateway Servers v10.6.1-3  who are going to expire their license soon: [Brightmail] (ERROR:3297.2048198400): [10202] The AntiSpam license will expire in 8 days

I have the new one, an enterprise suite license who has a Start Date of 22-JUN-16, and I'm trying to register it (https://support.symantec.com/en_US/article.HOWTO47...) but the following error appears:

Cannot register the specified license file.
Unable to complete registration with Symantec. You may have specified an invalid license file. Please specify a valid license file. No more information

Do I have to wait that day to register it? What is going to happen if the actual license expires in 21-JUN-16 and the other starts one day after (22-JUN-16)?

Thanks in advance!