About 20 minuntes ago we got this error:
09.03.2016 12:22:46(ver. 6.410) Download quota exceeded, skipping this file.
Possible Google Server download (type) quota exceeded on file (%File name%), skipping download to prevent data loss. MD5_1 5 System.Exception : sd criticality=0
Inner: Source: Syncdocs : sd criticality=0
We have full standard license, not expired.
Files are uploaded on a server but we can't download them on multiple PCs.
Update: everything is OK now. Seems like it was some Google Drive internal issue.
09.03.2016 12:05:24(ver. 6.410) Google Server error. Server might be too busy, or syncing backend. Stopping this sync and re-starting in a minute...
Backend Error 
Message[Backend Error] Location[ - ] Reason[backendError] Domain[global]
Google.GoogleApiException : sd criticality=7
Source: Google.Apis : sd criticality=7