Gmail API integration causing email sending failures

Other Questions Gmail
1

I’m developing an API that needs to send welcome emails using a Gmail account. Initially, it worked fine, but now I’m getting an error in Postman:

Invalid greeting. response=421 Service not available: 421 Service not available

I’ve tried solutions from similar issues, but no luck. Here’s my Adonis Mail config:

import env from '#start/env'
import { setupMailConfig, transportOptions } from '@adonisjs/mail'

const emailSettings = setupMailConfig({
  defaultProvider: 'smtp',
  senderInfo: {
    email: env.get('EMAIL_USERNAME'),
    name: 'Company Name'
  },
  replyToInfo: {
    email: '[email protected]',
    name: 'Support Team'
  },
  providers: {
    smtp: transportOptions.smtp({
      server: env.get('EMAIL_HOST'),
      port: env.get('EMAIL_PORT'),
      auth: {
        method: 'login',
        username: env.get('EMAIL_USERNAME'),
        password: env.get('EMAIL_PASSWORD')
      },
      encryption: false,
      forceTLS: true
    })
  }
})

export default emailSettings

declare module '@adonisjs/mail/types' {
  export interface ProviderList extends InferProviders<typeof emailSettings> {}
}

Any ideas on how to fix this? Thanks in advance!

2

I encountered a similar problem recently. It’s likely that Google has flagged your account for suspicious activity due to the API integration. To resolve this, try logging into your Gmail account directly and look for any security alerts or notifications. You might need to verify your account or approve the API access.

Additionally, ensure you’re using the correct SMTP settings for Gmail. The server should be ‘smtp.gmail.com’, port 587, and encryption should be set to TLS. If these are correct, consider implementing exponential backoff in your code to handle temporary service unavailability.

If the issue persists, you might want to explore using Google’s OAuth 2.0 for authentication instead of SMTP. This is generally more secure and less prone to these types of errors.

3

hey there! i had a similar issue. might be worth checking if your gmail account has 2FA enabled. if so, you’ll need to generate an app-specific password instead of using your regular password. also, double-check your email host and port settings. hope this helps!

4

I’ve dealt with this exact issue before, and it can be quite frustrating. One thing that often gets overlooked is Gmail’s security settings. Have you checked if your account has any restrictions on less secure apps? Sometimes, even if you’ve allowed them before, these settings can change after updates.

Another potential culprit could be IP restrictions. If you’re sending from a new IP or location, Gmail might be blocking it as a precaution. Try sending a test email manually from the same IP to see if it goes through.

Lastly, consider implementing rate limiting in your code. Gmail has strict limits on how many emails you can send in a given period. Exceeding these limits can trigger temporary blocks. Implementing a queue system for your emails could help manage this more effectively.

If none of these work, you might want to consider using a dedicated email service like SendGrid or Mailgun. They’re designed for high-volume sending and tend to be more reliable for API integrations.