Hi Patrick,
You should check your 'Faults' drop down for that specific dSource to get the full error message, some of the faults that are picked up are due to a background process that we run on each environment to ensure that best practices are being followed and some can alert you to more serious issues. In general the yellow icon is a warning and if you are aware of the alert you can safely 'Ignore' or 'Mark as Resolved'; if there is a red icon then there might be a more serious issue that needs to be addressed as it will affect the future usability of snapshots etc.
Hope that helps.