if you think it is any antivirus or firewall software blocking requests of your appication
1- check their "blocked program list"
2- you can install Fiddler its free and will show your whatever is being requested from your system, below is the link
if fiddler is showing you a request being made from your appication to gmail then
no software is blocking the request
. sorry that was my assumption as i'm not sure the sequence of software
will come into the picture. but you can keep it as alternate that your software is making a request. if it is showing your request i think its Gmail and like @nbgangsta said can result in spam. and in that case you can take support from gmail team.