Valid License Keys failing to Activate

My site uses FastSpring talking to LimeLM to generate a license. Our software has an interface for actually activating/deactivating licenses. I have customers buying the software successfully but when they try to activate the license key, LimeLM is sometimes returning that the key is expired or invalid.... then the same key might randomly work on the nth attempt.

More information is needed:

1. Version of TurboActivate you're using.

2. Exact function call that is failing.

3. Exact error code returned.

It sounds like these customers have misconfigured computers. Wrong timezone, time, date or all of the above. The error codes tell you exactly how to fix it.