I am having trouble signing into messages on my MBPr

[Hieveryone]

I have a late 2013 MBPr 2.6/8/256 running Mavericks 10.9.5

When I try to login to messages using my Gmail account it keeps asking for my password, and moments later I get an email from Gmail saying:

"Sign-in attempt prevented...someone tried to sign in to your Google Account from an app that doesn't meet modern security standards..."

How can I fix this?

 

[T5BRICK]

How can I fix this?

Which browser are you using? Is it a current version?

*edit*

I may be unclear on what you're trying to do...

 

[Hieveryone]

Which browser are you using? Is it a current version?

*edit*

I may be unclear on what you're trying to do...

You know the messages app in the toolbar? It's not a browser :/