Annual budget of &2 exhausted for &1

What causes this issue?

The annual budget of the availability control ledger &V2& has been
consumed for the GM account assignment &V1&. Availability control on
outgoing amounts raised this message for the following combination of
availability control ledger, fiscal year, and control object:
&V3&&V4&
<ZH>Note:</> The control object is defined for a grant/fund/sponsored
program/sponsored class/budget time slice.
DEFINE &N& = '001'
INCLUDE GMAVC_ANNUAL_MESSAGE_EXT

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.