I'm having the exact same issue. Let me guess, Enpass Helper becomes unusable after waking from sleep? The icon is still visible in the system tray but is seized and using the browser extension acts as if the helper isn't loaded.
I've tried every possible combination of boot scenarios to rule out conflicts with the only possible culprit being enpass helper having the problem.
I also have a Surface Pro 3 that is having a different problem with the Enpass helper; upon boot or trying to launch enpass helper, I get Windows stop message: C:\Program FIles..BLAH BLAH Enpass.exe An invalid name request was made. The name requested cannot be retrieved at this time.
At least on my desktop machine, a reboot will get me going again, but on my Surface Pro 3 Enpass extensions are unusable which makes more steps needed to use Enpass. Please advise how I can fix these issues or refund my $20 I've spent across several devices to use Enpass instead of others.