Clients definition are not update from last few days. Users are senior and criticial profile.

So require to resolve the problem in a single visit so please help for the troubleshoot?

Any technical person share the troubleshoot step? 

What is your SEP version?

Run the symhelp to resolve it

Download the Symantec Help (SymHelp) diagnostic tool to detect Symantec product issues

--Edit--

Try it

http://www.symantec.com/business/support/index?page=content&id=HOWTO59193

console is 12.1.3001.165 client is 11.0.7400.1398.

how to run the tool?

SEP 11.x support is end at 5th jan 2015.

On January 5th, 2015, Symantec Endpoint Protection 11.0.x and Symantec Endpoint Protection Small Business Edition 12.0 will reach End-of-Support-Life and no longer be entitled to support, LiveUpdate, virus definitions and security updates. To remain protected, ensure all of your endpoints have been migrated to version 12.1 and activate the advanced protection available through Insight reputation scoring and SONAR behavioral monitoring. Endpoints that continue to run Endpoint Protection 11.x and SBE 12.0 after End-of-Support Life (EOSL) will no longer receive virus definitions, content updates, break fixes, patches, workarounds or technical support

https://www-secure.symantec.com/connect/blogs/did-you-get-security-memo-symantec-endpoint-protection-11-eosl

--Edit--

Symantec Endpoint Protection 11.0.x End of Support Life

 You are require to upgrade your SEPM in 12.1 RU5

Upgrade or migrate to Symantec Endpoint Protection 12.1.5

Additional

If client is 11.x then no require to run symhelp tool, for your knowledge all information for running is available in above attach comment

How to run and use Symantec Help (SymHelp) reports

SEP 11 clients may receive untested definitions via the 12.1 SEPM for a few additional months. However, they will not be available via LiveUpdate or SEPM 11

https://www-secure.symantec.com/connect/blogs/did-you-get-security-memo-symantec-endpoint-protection-11-eosl

Your SEP 11.x clients wont receive updates as they are end of support life

https://www-secure.symantec.com/connect/forums/symantec-endpoint-protection-110x-eosl

https://www-secure.symantec.com/connect/blogs/did-you-get-security-memo-symantec-endpoint-protection-11-eosl

However, if connected to a 12.1 SEPM they may possibly receive untested defs.

Thankyou i share the article to senior.