Email being blocked sent from mac mail 505 error

Hi studiolionmg,

Since the Mail app is working in the new user, with your email account, this tells us the issue is user specific, and not system-wide.

Next, follow the steps under, "Temporarily prevent items from opening automatically when you log in," from this article: Open items automatically when you log in on Mac. This step will allow you to see if there may be any items which are opening when you log into your user which may be preventing Mail from working.

Once you're at the desktop for your user, try sending a piece of email. If the mail sends with the login items disabled, you'll want to follow the steps from the "Add or remove automatic items" of the same article. You can remove them all at once, or you can remove them one at a time until you find which item is causing the issue. Removing a login item will not affect the app from running on your computer. It will just no longer startup automatically.

If you find you need more assistance; contact Apple Support here: Get Support.

Have a great day!

studiolionmg wrote:

I have a gmail account with a custom domain name and I am having this problem on the latest version of MacOS and the version prior. I have a mail butler plugin but the issue happens with or without it installed.

Problem: I have some emails that are sent from Mac Mail desk top client that get blocked, 505 error. However if i send to the same email address from a browser logged into my gmail account it gets sent with no issue. I even tried a different mail client (mimestream) and the email was sent with no issues.

I have even received emails from people and my response gets a blocked 505 error. When I try to send a new thread it gets blocked too. The only way I can send emails or reply to these people is using the web based client or mimestream.

Error 505. The web/mail server does not support, or refuses to support, the HTTP/SMTP protocol version specified by the client (e.g. your Web browser/mail client in the HTTP/SMTP request data stream sent to the server.

If you use a non-iCloud SMTP server, don't use your iCloud email address as a "Send From" address. Otherwise, your email might not deliver or it might deliver to the recipient's Junk folder.

ref: Get help using iCloud Mail - https://support.apple.com/en-us/HT203528

This would be true for your gmail account as well, verify the sending receiving email is the same email address..

If it suspects a spoof, it may refuse to authenticate it with a mis-match.

The clue is the fact the browser mail sends and receives without issue. Something in the Mail.app client needs to be changed for your problem account.

studiolionmg wrote:

I created a new user as instructed and added the new email that I created and it worked. This creates a new set of questions as I just bought this new iMac and I set it up fresh without loading everything from a backup in hope of not moving this issue from the old mac to the new mac. So then why did creating a new user make it work but setting up a new computer fresh did not? With this information why do I need to do next?

I can not answer your question directly— however

I can say that one trouble shooting technique for sorting issues and/or anomalies, is to simply delete the problem account and then add in back in anew. All IMAP mail stays on there server so there is no loss of data there.

good luck !

HI studiolionmg,

You mentioned that you created a new email account. This tells us that it's not just related to your email account, but may be related to the server settings.

Did you follow the steps in this article to create a new user on your Mac? Creating a new user on the Mac will allow you to isolate the issue further. Follow these steps to create the new user: Set up users, guests, and groups on Mac. Once the new user is created, you'll want to try using your primary email account.

If the issue persists with the new user, reach out to the Apple Support team for further assistance. You can contact Apple Support here: Get Support.

Take care.

Hello studiolionmg, 

Welcome to the Apple Support Communities! We understand you are receiving a 505 error when trying to send mail through the Mac Mail client with your custom domain name. With the issue isolated to the Mail app on your Mac, and not other mail clients, this indicates there may b e an issue with the server settings. 

Based on this information, first run Connection Doctor in Mail to check and see if there are any issues detected. This article will show you how to do so: Use Connection Doctor in Mail on Mac. 

You can use this article to gather the necessary email settings which you may need to set up your account manually with your custom domain name: Mail settings you might need from your email provider. You'll want to verify these settings with Gmail, as you can access the data from their webmail portal.

All the best.

Hi studiolionmg,

We appreciate you taking the time to run Connection Doctor and check the server settings. Previously you were seeing error 505, and now you're seeing a 550 error. If this is correct, check and see which port is being used for the SMTP server.

Change Server Settings in Mail on Mac

If the issue persists, try creating a new user, sign into that new user with your information, and test it out again. This article will show you how: Set up users, guests, and groups on Mac.

Take care.

No worries, studiolionmg!

Let us know if the issue persists with the new user, or if you're able to send the messages using the native macOS Mail app.

If you can send messages through the Mail app, the next step will be to see if you're running any type of security software which could be blocking the access Mail requires.

We look forward to hearing the results.

Enjoy the day!