Smtp server

Think I saw your other topic first:
Email alert configuration

You could leverage O365 as a relay if you'd like. It does take some additional configuration, but could be a good workaround solution if you don't have your own email server for SMTP.

https://support.solarwinds.com/SuccessCenter/s/article/Send-Orion-alert-emails-using-Office-365-and-Outlook?language=en_US

I think there's one for google, but you have to allow less secure apps, which I'm not sure if they allow anymore or not..