Audiocodes Mediant SBA Lyss error

Bumped into an error:

Log Name:      Lync Server

Source:        LS Storage Service

Date:          5/16/2017 5:54:02 PM

Event ID:      32071

Task Category: (4006)

Level:         Error

Keywords:      Classic

User:          N/A

Computer:     xxx

Description:

Storage Service had a failure while refreshing its calculation of DB space used.

DB Space Used Refresh Error. Object reference not set to an instance of an object.

Cause: The Timer task to refresh the DB space used value ran into an exception. This action will be retried and should auto recover.

Resolution:

Check event details. If problem persists, notify your organization's support team with the event details.

For the moment, not clear what causing it.

Option I consider for the moment are:

install latest Lync CU

install windows patches inside SBA (esp. .NET)

reset fabric

repair fabric

redeploy CS databases

repair SBA image and re-deploy from scratch

some relevant links I collected so far:

https://technet.microsoft.com/en-us/library/jj945604(v=ocs.15).aspx

https://d1it.wordpress.com/2014/01/26/lync-2013-sba-front-end-service-fails-to-start/

http://ucready.com/lync-front-end-service-rtcsrv-wont-start/

https://www.softwareab.net/wordpress/lync-server-2013-front-end-event-32174/

https://social.technet.microsoft.com/Forums/ie/en-US/ada3e098-5e17-4568-9349-81b6c20d1963/lync-2013-problem-with-lyss-database-operation-getlyssdbusage?forum=lyncdeploy

https://social.technet.microsoft.com/Forums/lync/en-US/6d68e1d1-43b3-4917-aa52-1b7f78ab356e/lyss-database-error-in-lync-log-on-the-front-end-server-enterprise-edition?forum=lyncdeploy

update: nothing really helped, we did completely redeploy from usb key.