Bulk Email Limited to 80 Emails (GMAIL)?

Question

Gmail list their email limits here:

https://support.google.com/a/answer/166852?hl=en

However, I am getting an SMTP Exception with little more info than "failure sending mail". It is happening at the 80 email mark, when attempting to rapidly send a bulk volume of emails.

My error catching is:

       try
            {
                fLogFile.Add("Before smtp.Send");
                smtp.Send(mail);
                fLogFile.Add("After smtp.Send");
                Result.SentCount = 1;
            }
            catch (System.ArgumentNullException e)
            {
                fLogFile.Add("Argument Null Exception");
            }
            catch (System.ArgumentException e)
            {
                fLogFile.Add("Argument Exception");
            }
            catch (System.ObjectDisposedException e)
            {
                fLogFile.Add("Object Disposed Exception");
            }
            catch (System.Net.Mail.SmtpFailedRecipientsException e)
            {
                fLogFile.Add("SMTP failed recipients exception");
            }
            catch (System.InvalidOperationException e)
            {
                fLogFile.Add("Invalid Operation Exception");
            }
            catch (System.Net.Mail.SmtpException e)
            {
                fLogFile.Add("Smtp Exception");
                fLogFile.Add(e.Message);
            }

Can anyone confirm if 80 emails is a bulk limitation? I haven't seen Google state any limits on rapid email requests.

Answer 1

I think there is a per minute limit for sending SMPT messages via Gmail (around 80 (had the same experience) to 100).

First, check your message queue in G Suite admin area. If the queue is huge and still growing you send too fast.

Some useful links:

• G Suite SMTP Error Reference
• Gmail Bandwidth limits for accounts
• Gmail sending limits in G Suite
• Bulk Senders Guidelines

There is no further explanation what's wrong when you suffer from the error

421, "4.7.0", Try again later, closing connection.

In general, Gmail may slow-down or reject your emails if you:

• send too large volumes of email.
• suddenly change your email volume.
• send email to spam honeypot addresses.
• send email to unknown users.
• your server’s IP is on a public blacklist.
• Gmail users marking your messages as spam.
• use a new IP address to send emails.
• your DNS settings are incorrect.

Moral: If sending a large amount of email, it's probably best to use your own email server.