yahoo mail retreival from gmail - POP settings

I have configured my gmail to retreive emails from yahoo mail id.
(This helps in a way , you don't have to login to two accounts to check for email
at the same time, maintain two mails for two different purposes.

I was having yahoo mail id for a  long time and when I tried switching back
to gmail, it was painful to broadcast all users about my yahoo mail id.
So, I have configured gmail to retrieve emails from yahoo id automatically
using "Account and Import" in gmail settings.)

I have been happily receiving emails long time since, but all of a sudden
it stopped working.

While looking for the solutions around, I thought of just logging into yahoo
and check the settings.


I have just save relevant settings in Yahoo to enable POP as well as
re-entered password in gmail. Cool...it started working again.

Note, I have not done anything new, just save settings in Yahoo and just
enable the same in gmail. I think its kind of reboot.
These things happen in software world  ;)

PS:
Error  messaege observed in gmail.
Error in RETR command: [SYS/TEMP] problem retrieving message