Please does anyone have an idea how i can resolve this error "Failure to access the DBMS server [[Microsoft][SQL Server Native Client 11.0]Communication link failure]"

[IreneEgbulefu1]

I am trying to compress one of my geodatabase on SDE 10.4 but i keep getting this error below. My native client is version 11 and 64 bits and this error is just peculiar to 2 geodatabases out of the 7 geodatabases that I have on my server

ERROR 999999: Error executing function.

Failure to access the DBMS server [[Microsoft][SQL Server Native Client 11.0]Communication link failure] [sde.DEFAULT][STATE_ID = 15]

Underlying DBMS error [HY000:[Microsoft][SQL Server Native Client 11.0]Unspecified error occurred on SQL Server. Connection may have been terminated by the server.] [sde.DEFAULT]

Failed to execute (Compress).

Rebecca Strauch,

gis servers‌, sde connection microsoft sql server 2012‌, 

[Asrujit_SenGupta]

Check the Direct Connect log files and provide us the error here if any..

[IreneEgbulefu1]

Do you mean the ArcGIS Server logs

[Asrujit_SenGupta]

No, the sdedc log file will be present in: C:\Users\%your_user_profile%\AppData\Local\Temp

Open it using Notepad and check for error towards the end of the file.

[IreneEgbulefu1]

CAN'T OPEN INSTANCE: sde:sqlserver.
Spatial Engine Connection Failed (-409).
Cannot Get Access to Instance sde:sqlserver

[Asrujit_SenGupta]

That doesn't really help much.

This Bug is similar: Bug: Compress operation fails after encountering a corrupt spatial index when a SQL Server 2008 R2 d... 

If possible, re-create the Spatial Index for the data in the Geodatabase and check if that helps.