Sharing by email not working

I have used the share by email option several times in the past, however, lately it has not been working. It gives me an error every time, no matter who I try to email to. This is the error that I get:


Sending failed...

Traceback (most recent call last):
File "site-packages\calibre\gui2\email.py", line 44, in run
File "site-packages\calibre\gui2\email.py", line 134, in sendmail
File "site-packages\calibre\utils\smtp.py", line 135, in sendmail
File "site-packages\calibre\utils\smtp.py", line 127, in sendmail_direct
IOError: Failed to send mail: error(10060, 'A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond')


Just curious as to what is happening and how I can fix it?