Error sending email by Gmail account

When I tried to send an invoice to a client today I got the following error (in Dutch):

System.Net.Mail.SmtpException: System.Net.Mail.SmtpException: Voor de SMTP-server is een beveiligde verbinding vereist of de client is niet geverifieerd. Het serverantwoord is: 5.5.1 Authentication Required.

It seems that Google changed some security issues, as I got an email (again: in Dutch) on this error:

Google heeft zojuist voorkomen dat iemand inlogde op uw Google-account vanuit een app die een mogelijk risico vormt voor uw account. Minder veilige app maandag 4 juni 2018 13:38 (CET) Amsterdam, Nederland* Herkent u deze activiteit niet? Als u niet onlangs een fout heeft ontvangen toen u probeerde toegang tot een Google-service (zoals Gmail) te krijgen vanuit een niet-Google-app, is het mogelijk dat iemand uw wachtwoord heeft.

You will now need to specifically accept ‘unsafe connections’ in your Gmail account for Gmail to work again.
Or Manager should achieve the status ‘Secure App’ by Google so everything for persons using Gmail as SMTP server for sending e-mails from Manager will work again.

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Gmail has permanently blocked access to the application ‘Manager’. You can no longer send invoices via Gmail. This sucks!

I have successfully sent an email using my gmail account and Manager Desktop version 22.6.9 on a Windows 10 PC

This is simply not true. As a new member, it’s recommended you first search the guides and the forum before starting a new topic. If you follow this guide, you’ll see it works well.



It seems Gmail enhanced the security - Previous settings no longer works - requests “secure connection” Checked with “Gmail” says it requires additional security as safety since 30 May 2022. See pic annexed hereto. I had to recreate all my gmail accounts on Office 2019 to enable them to work with IMAP seems POP is a problem with Gmail now. Manager email also nolonger works for me.

Welcome to the forum @Eden_Flowers.

“Allowing less secure apps” and “secure connection” aren’t the same thing.

The connection is already secured using SSL/TLS. What less secure apps mean that apps that don’t use 2 factor authentication.

Even then, allowing less secure apps is an optional step since you can always use single app password as described in this guide:

Just skip step 2.