try signing in using your cc desktop app.
if you see the same message, confirm that you can connect to the secure adobe servers by reading, http://helpx.adobe.com/x-productkb/policy-pricing/activation-network-issues.html do you see both logos?
if you can and still see a connection error, white list the adobe network endpoints, https://helpx.adobe.com/enterprise/kb/network-endpoints.html
Thank you fo your reply!
The actual issue in my case was AVG Tuneup Software who forced some background services sleep!
I am having this problem again.
As you stated
I can see both logos on http://helpx.adobe.com/x-productkb/policy-pricing/activation-network-issues.html
But I am still getting error!
Newbie here. May you please tell how to white list the adobe network endpoints?
google your router and/or firewall for how to add to your white list.
but, if you solved the problem before by doing something with other software (eg, avg tuneup), white listing adobe endpoints won't help.
why did the problem return? ie, check av, antimalware, cleaner, tuneup, defragger software on your computer that might cause the problem. then you need to stop those programs or, at least, stop them from interfering with adobe processes.