I’m having trouble with the Gmail API in my .NET project. My code creates an email using MailMessage, converts it to a MimeMessage, and sends it through the API. The weird thing is, the API doesn’t show any errors and I can see the email in my sent folder. But then I get this bounce message:
Bounce <[email protected]>
An error occurred. Your message was not sent.
Has anyone run into this before? I’ve tried debugging but can’t figure out what’s going wrong. Here’s a simplified version of my code:
Dim email = New MailMessage()
email.Subject = "Test Subject"
email.To.Add("[email protected]")
email.From = New MailAddress("[email protected]", "Sender Name")
email.Body = "<p>This is a test email.</p>"
email.IsBodyHtml = True
Dim mimeMessage = MimeMessage.CreateFromMailMessage(email)
Dim rawMessage = New Message()
rawMessage.Raw = ConvertToBase64Url(mimeMessage.ToString())
GmailService.Users.Messages.Send(rawMessage, "me").Execute()
Function ConvertToBase64Url(input As String) As String
Dim bytes = Encoding.UTF8.GetBytes(input)
Return Convert.ToBase64String(bytes).Replace("+", "-").Replace("/", "_").TrimEnd("="c)
End Function
Any ideas on how to fix this? Working with Google APIs can be so frustrating sometimes!
hey there bob, i’ve had similar issues before. have you checked if the recipient email is valid? sometimes gmail api can be picky about that. also, try adding a plain text version of the body alongside the html one. that helped me once. good luck troubleshooting!
I’ve encountered this issue before, and it can be quite frustrating. One thing to check is your sender email authentication. Make sure you’ve properly set up SPF, DKIM, and DMARC records for your domain. These are critical for email deliverability. Another potential cause could be the content of your email. Some recipients’ spam filters might be flagging your messages. Try sending a simple plain text email without any links or attachments to see if it goes through. Lastly, double-check your API credentials and make sure you have the necessary permissions to send emails. Sometimes, API scope issues can cause silent failures like this. If none of these solve the problem, you might want to look into using a dedicated email delivery service alongside the Gmail API for better deliverability and debugging options.
I’ve dealt with similar Gmail API headaches before, Bob. One thing that’s not immediately obvious is the importance of the ‘From’ address. Make sure it matches exactly with the email address associated with your Google account or a verified ‘Send as’ address in your Gmail settings. Otherwise, Google might silently reject the email without throwing an API error.
Another potential gotcha is the MIME formatting. Sometimes the auto-generated MIME from MailMessage can be a bit wonky. You might want to try constructing the MIME message manually using MimeKit for more control. This way, you can ensure all headers are properly set.
Lastly, don’t forget about rate limits. If you’re sending a lot of emails in quick succession, you might be hitting Gmail’s limits without realizing it. Consider implementing some delay between sends or using batch requests if you’re doing bulk emails.
If all else fails, Google’s Email Log Search in the Admin console can be a lifesaver for debugging these kinds of issues. It gives you a detailed view of what’s happening to your emails after they leave your code.