Hello,
Are they using Exchange? Or is it Gmail or what are they using?
You can use send email v2 from within your flow, but create a connection using other credentials.
The only other way is
a) if that provider has a connector (and you haven't said who it is so I dont know)
b) use the HTTP Connector to talk to their SMTP end point (assuming they have one, or if they have an API)
There are several ways but it depends on their end points, how its protected etc.
Cheers
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Thank You
Michael Gernaey MCT | MCSE | MCP | Self-Contractor| Ex-Microsoft
https://gernaeysoftware.com
LinkedIn: https://www.linkedin.com/in/michaelgernaey