Greetings, fellow night owl,

nightowl 写道：
> Why would the old computer say the certificate is invalid while 
> two of
> my newer computers say it is ok?

That sounds like your old computer's system clock isn't set to the 
correct time.  You can check it with ‘date’, and change it with 
‘date --set="…"’.

If your clock was off, and you do make changes, it may be 
necessary to save them to the hardware clock (so they survive 
reboots) with ‘hwclock --systohc’.  I'm not sure whether that's 
done automatically nowadays.

Kind regards,

T G-R