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Log in as a user with the 'Jira Administrators' global permission.
Navigate to Admin menu → Manage apps. Select SLA PowerBox → Notification Providers to open the SLA Notification Providers page.
Tip: Keyboard shortcut: g + g + start typing notification providers...Click the Add Provider button.
Select your Provider Type:
Confirm your choice with the Next button.
You will be redirected to the Create Notification Provider page. Follow the configuration steps specified for each Provider type.
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Useful links:
www.twilio.com,
www.support.twilio.com
www.slack.com/get-started/
www.clxcommunications.com
https://www.smsapi.com/en
www.stride.com
https://confluence.atlassian.com/adminjiraserver075/configuring-jira-s-smtp-mail-server-to-send-notifications-935391635.html