Virus Definition is not updating correctly in two server

Hello. I have a Console runing Syamnter Endpoint Protection Small Business Edition 12.1.1000.157

I have installed the agent in many different servers.

I have two servers now that are not updating the virus definition and from the last day that was updated, is not running scan also.

I happen before with other servers and the only way that I found to make it work was restart the server or in the worst case, uninstall teh AV and reinstall it.

The problem with this server is that they are in production 24x7. I can't restart it. To do it I have to request a Maintenance Windows with 1 month in advance.

There are some way that I can make it work?

Thanks