My outgoing google password is not working. It works on my phone but not on my computer. My incoming password works. What do I need to do?

My existing password for the google server is not working with my e-mail system. As of this morning, I have been unable to send e-mails as I keep getting the message that my password is not correct. I am able to log into my e-mail and receive e-mails but I can not send e-mails. Everything was working yesterday but not today. I made sure my e-mail was up to date. I have closed out and reopened my e-mail but it is still not working. I know the password is correct as it works on my phone. I am able to send and receive on my phone. So I am thinking it is something in my e-mail program that is causing this issue. How do I fix this?