Error while trying to setup SMTP

[SepidehAzemati]

Hi,

I am constantly getting error 5.7.0 on my app provider website when I try to setup SMTP. 
It has to be mentioned that my email (info@....com) is provided by Gmail (google workspace) and we are already using google workspace and want to send and receive emails from the third-party application (mindbody).

Any solution for this?

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