asp.net using from to how Sending email through Gmail SMTP server with C#
THE FOLLOWING WILL ALMOST CERTAINLY BE THE ANSWER TO YOUR QUESTION IF ALL ELSE HAS FAILED:
I got the exact same error, it turns out Google's new password strengh measuring algorithm has changed deeming my current password as too weak, and not telling me a thing about it (not even a message or warning)... How did I discover this? Well, I chose to change my password to see if it would help (tried everything else to no avail) and when I changed my password, it worked!
Then, for an experiment, I tried changing my password back to my previous password to see what would happen, and Gmail didn't actually allow me to do this, citing the reason "sorry we cannot allow you to save this change as your chosen password is too weak" and wouldn't let me go back to my old password. I figured from this that it was erroring out because either a) you need to change your password once every x amount of months or b). as I said before, their password strength algorithms changed and therefore the weak password i had was not accepted, even though they did not say anything about this when trying to login ANYWHERE! This (number 2) is the most likely scenario, as my weak password was about 4 months old, and it let me use it in Gmail.
It's pretty bad that they said nothing about this, but it makes sense. Because most hijacked emails are logged into using software outside of gmail, and I'm guessing you are required to have a stronger password if you want to use Gmail outside of the Gmail environment.
I hope this helps!
For some reason neither the accepted answer nor any others work for me for "Sending email in .NET through Gmail". Why would they not work?
UPDATE: I have tried all the answers (accepted and otherwise) in the other question, but none of them work.
I would just like to know if it works for anyone else, otherwise Google may have changed something (which has happened before).
When I try the piece of code that uses
SmtpDeliveryMethod.Network, I quickly receive an SmtpException on Send(message). The message is
The SMTP server requires a secure connection or the client was not authenticated.
The server response was:
5.5.1 Authentication Required. Learn more at" <-- seriously, it ends there.
This is a question that I asked a long time ago, and the accepted answer is code that I've used many, many times on different projects.
I've taken some of the ideas in this post and other EmailSender projects to create an EmailSender project at Codeplex. It's designed for testability and supports my favourite SMTP services such as GoDaddy and Gmail.
Turn On Access For Less Secure Apps and it will work for all no need to change password.
Dim SMTPClientObj As New Net.Mail.SmtpClient SMTPClientObj.UseDefaultCredentials = False SMTPClientObj.Credentials = New System.Net.NetworkCredential("email@example.com", "mypwd") SMTPClientObj.Host = "smtp.gmail.com" SMTPClientObj.Port = 587 SMTPClientObj.EnableSsl = True SMTPClientObj.Send("firstname.lastname@example.org","email@example.com","test","testbody")
If you get an error like "The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at" as I get before this, make sure the line
SMTPClientObj.UseDefaultCredentials = False included and this line should before the
I did try to switch these 2 lines the opposite way and the 5.5.1 Authentication Required error returned.
The problem is not one of technical ability to send through gmail. That works for most situations. If you can't get a machine to send, it is usually due to the machine not having been authenticated with a human at the controls at least once.
The problem that most users face is that Google decides to change the outbound limits all the time. You should always add defensive code to your solution. If you start seeing errors, step off your send speed and just stop sending for a while. If you keep trying to send Google will sometimes add extra time to your delay period before you can send again.
What I have done in my current system is to send with a 1.5 second delay between each message. Then if I get any errors, stop for 5 minutes and then start again. This usually works and will allow you to send up to the limits of the account (last I checked it was 2,000 for premier customer logins per day).
Simple steps to fix this:
1)Sign in to your Gmail
2)Navigate to this page https://www.google.com/settings/security/lesssecureapps & set to "Turn On"
If nothing else has worked here for you you may need to allow access to your gmail account from third party applications. This was my problem. To allow access do the following:
- Sign in to your gmail account.
- Visit this page https://accounts.google.com/DisplayUnlockCaptcha and click on button to allow access.
- Visit this page https://www.google.com/settings/security/lesssecureapps and enable access for less secure apps.
This worked for me hope it works for someone else!
I also found that the account I used to log in was de-activated by google for some reason. Once I reset my password (to the same as it used to be), then I was able to send emails just fine. I was getting 5.5.1 message also.
I was using corporate VPN connection. It was the reason why I couldn't send email from my application. It works if I disconnect from VPN.
Another thing that I've found is that you must change your password at least once. And try to use a secure level password (do not use the same user as password, 123456, etc.)
Yet another possible solution for you. I was having similar problems connecting to gmail via IMAP. After trying all the solutions that I came across that you will read about here and elsewhere on SO (eg. enable IMAP, enable less secure access to your mail, using https://accounts.google.com/b/0/displayunlockcaptcha and so on), I actually set up a new gmail account once more.
In my original test, the first gmail account I had created, I had connected to my main gmail account. This resulted in erratic behaviour where the wrong account was being referenced by google. For example, running https://accounts.google.com/b/0/displayunlockcaptcha opened up my main account rather than the one I had created for the purpose.
So when I created a new account and did not connect it to my main account, after following all the appropriate steps as above, I found that it worked fine!
I haven't yet confirmed this (ie. reproduced), but it apparently did it for me...hope it helps.
We strongly recommend that you use a secure app, like Gmail, to access your account. All apps made by Google meet these security standards. Using a less secure app, on the other hand, could leave your account vulnerable. Learn more.
smtp.UseDefaultCredentials = false;
smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);
I had this problem resolved. Aparently that message is used in multiple error types. My problem was that i had reached my maximum of 500 sent mails.
log into the account and manually try to send a mail. If the limit has been reached it will inform you
smtp.Host = "smtp.gmail.com"; //host name smtp.Port = 587; //port number smtp.EnableSsl = true; //whether your smtp server requires SSL smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network; smtp.Credentials = new NetworkCredential(fromAddress, fromPassword); smtp.Timeout = 20000;