SEN stands for Support Entitlement Number that identifies the product and helps us know what support you need.
A valid SEN is always needed, for support purposes about our products.
Go to Jira Administration → Manage apps → Manage apps and click over the product:
Go to Jira Administration → Manage apps → Manage apps and click over the product:
Go to Settings → Apps → Manage apps and click over the product:
Go to Settings → Apps → Manage apps and click over the product: