Thanks for reaching out to Jotform Support. Our Portuguese Support agents are busy helping other Jotform users right now, so I'll try to help you in English using Google Translate, but you can reply in whichever language you feel comfortable using. Or, if you'd rather have support in Portuguese, let us know and we can have them do that. But, it might take a while until they're available again.
Now, coming back to your question, may I know if you have enabled the two-step verification in your Google account? If not, this is one of the requirement before you can use Gmail SMTP. For more information, see how to turn on two-step verification. You should also create an app-specific password for Jotform SMTP. Let me show you how: