Alert mails are not being sent out in Grafana

We want to receive an alert for Utilization thresholds but we are receiving below error.

From the same Machine when we send mails using SMTP(internal) and using PowerShell we are able to send mails.

t=2021-07-06T07:13:16-0400 lvl=eror msg=“Failed to send alert notifications” logger=context userId=2 orgId=1 uname=XXX error=“Failed to send notification to email addresses: xxx@abc.com: dial tcp [::1]:25: connectex: No connection could be made because the target machine actively refused it.” remote_addr= . . .*
t=2021-07-06T07:13:16-0400 lvl=eror msg=“Request Completed” logger=context userId=2 orgId=1 uname=XXX method=POST path=/api/alert-notifications/test status=500 remote_addr=
. . .* time_ms=1309 size=48 referer=http://vw*.xxx.local:3000/alerting/notification/1/edit

Grafana 8.0.1 Version
OS : Windows 10