Keep losing Visual Build license

[Too_Tall_Crown_Victoria]

We are using VBP version 7.2a. We keep loosing our license every so often. I have not been able to pinpoint a situation or timing yet. However, it is causing problems where nightly builds are not running due to the loss of the license.

Can you please give some guidence as to why we loose our license, what I should look at to see if we are doing something on our side, or how we can prevent this?

Until version 7.2a we did not have any issues like this. I have a second 6.0 license and that has never lost it's license.