What can cause the dashboard reporting that latest definitions on Symantec are not available?

The SEPM can reach *.symantec.com and the liveupdate seems to work

What happens after a refresh of the home page? How long has it been like this? Just start?

After a refresh nothing changes.

I've seen this behaviour in this moment but I don't know the start of this issue.

and no proxy? might want to double check nothing changed there.

Might be a proxy which is blocking

are you able to open this site in  browser?

http://liveupdate.symatnecliveupdate.com?

Windows Latest Symantec Version: Information not available in SEPM homepage

I confirm I can reach all *.symantec.com via browser.

http://securityresponse.symantec.com/avcenter/venc/auto/defstats.xml and I see this

I get this when I click 

http://securityresponse.symantec.com

I think thats where its broken

http://securityresponse.symantec.com as this is not covered by the wildcard used in *.symantec.com.

I've tried the link in the technote, that is different

I've the same your output if I check http://securityresponse.symantec.com

navigate to 

:\Program Files (x86)\Symantec\Symantec Endpoint Protection Manager\tomcat\logs

open sepm log file

does it show 

java.net.UnknownHostException: securityresponse.symantec.co

If yes then uncheck the enhanced security in IE as per this document

https://www.symantec.com/business/support/index?page=content&pmv=print&impressions&viewlocale&id=TECH104682

in sepm.log I don't have those entries (and IE ESC is disabled for both administrators and not).

But, in sepm.log I've this:

mar 06 2014 19:19:02 [localhost-startStop-1] [WARN ] [com.symantec.sepm.framework.properties.EncryptedPropertyPlaceHolderConfigurer] - Could not load properties from class path resource [com/symantec/sepm/framework/common/config/jdbc.properties]: class path resource [com/symantec/sepm/framework/common/config/jdbc.properties] cannot be opened because it does not exist

I dont have same message but my dash board works fine, that should be an issue then.

Do you use proxy and those settings are rightly set inside the SEPM ?

 it acutally goes here to check the latest defs,

You need to check your IE, if system account is able to access that URL

http://www.symantec.com/business/support/index?page=content&id=TECH146632