Email Not Sending

My emails won’t send, I checked the email settings and everything is correct, whenever i retry te error message states “The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Authentication Required. Learn more at”

but there isn’t any information to click from the learn more at.
Please help.

I have the same using the app on Mac IOS

Read the Guide: Troubleshoot email issues | Manager. Follow all relevant links. If the problem is not resolved, provide all requested information. Just saying “My emails won’t send” or “I have the same” provides no information for anyone to help you.

Thank you for taking the time to respond. Here are the information I have,

When ever I try changing the port the only other option is 25 and once its’s on that and I try to send out emails to my customers is says Failure sending mail.

My system inform -
Intel(R) Core™ i3-4030U CPU @ 1.90GHz 1.90 GHz
RAM- 8.00 GB
System type 64-bit operating system, x64-based processor
Windows 10 Pro
Storage -500gb

Manager version installed -v 22.68.73
Manager edition - Desktop.

Edit - Less-Secure-Apps has been discontinued for gmail and 2-step verification is now required.
Google Gmail | Manager