Already done all this things (from equinux support):
I'm given a 'Server Certificate error' during Activation?
Are you seeing a 'Server certificate' error message whilst activating your equinux software?
One likely cause is your system's date & time: Make sure your system clock is set correctly by checking 'Set date & time automatically' under System Preferences > Date & Time.
We also use a fairly new security certificate to protect your data. However, older versions of OS X might not immediately recognize the certificate.
To make sure OS X will recognize the certificate, you could try one of the following two fixes:
Run Software Update
Go to the menu and select 'Software Update'
Install any available system updates
Afterwards, restart and try activating again
Disable your firewall
Please make sure you are not running any firewalls which may block access to our activations server. Applications you may wish to disable temporarily include:
Mac OS X Firewall
LittleSnitch (Litte Snitch Configuration - Preferences … - General - Stop)
Check your Keychain
Open: Application > Utilities > Keychain Access
Select "Keychain Access > Keychain First Aid"
Enter your OS X account password, select Repair on the right and hit Start
Accept the certificate manually
Open Safari (not Firefox or Opera)
Go to the equinux Online store
When prompted, select 'Show certificate'
Check the box labeled 'Always trust www equinux com' and hit 'Continue'
Restart your equinux software and try activating again
You should now be able to activate your software using your equinux ID and password.