There's not enough information (OS, etc) for any detailed answer so generally speaking...
- Try turning off any screen savers or power saving features which may be in some way playing into it.
- Turn off any power saving settings which may be putting USB ports to sleep if this may apply to your setup.
- Look over the general optimization settings in the Presonus Knowledge Base
http://support.presonus.com/hc/en-us for Studio One 2 and whatever OS you are using to see if some of the suggestions there may help resolve the problem.
As a last resort, make a support ticket to see if one of the support representatives can help to resolve it. If so, please provide relevant information such as which version of Studio One 2 (2.6.5 or something earlier), operating system and version, etc.