Personnel number in critical area of interval &1 of object &2

What causes this issue?

A number range interval has exceeded a critical limit.

System Response

A warning is generated.

How to fix this error?

Inform your system administrator. The statuses of the number ranges for
object RP_PREL must be checked. One of them has exceeded a defined
critical threshold.

Procedure for System Administrators

The statuses of the number ranges for object RP_PREL must be checked.
One of them has exceeded a defined critical threshold.

Error message extract from SAP system. Copyright SAP SE.