
If your mail app checks for new messages more than once every 10 minutes, the app’s access to your account could be blocked.
Make sure your mail app isn't set to check for new email too frequently. Depending on your Google accounts security settings, you may need to. Enable either STARTTLS or SSL/TLS, not both. If using SSL/TLS directly with MAILUSESSL True, then use MAILPORT 465. If using STARTTLS with MAILUSETLS True, then use MAILPORT 587. Try signing in directly on the Gmail app. The port must match the type of security used. The email client's sign-in method might be insecure. If the tips above didn't help, visit and follow the steps on the page. If you recently changed your Gmail password, you might need to re-enter your Gmail account information or completely repeat your Gmail account setup on your other email client. Here, click on the CREATE CREDENTIALS button. After you enable the Gmail API, you should be redirected to the Gmail API Overview page. On the Gmail API page, click on the blue Enable button. Email reader programs such as Thunderbird or Evolution are great, but sometimes they can feel bloated. Allow less secure apps: If you don't use 2-Step Verification, you might need to allow less secure apps to access your account. Then look under Category and click on Email, or enter Gmail API in the search bar. Important: If you sign in with OAuth, use your regular Google password.
Use an App Password: If you use 2-Step Verification, try signing in with an App Password.Update your email client to the latest version.If you have these problems or can’t sign in, first check to make sure you’re using the right password.