Purchasing organization & does not exist

How to fix this error?

Please check whether you have entered the
<GL:purchasing_organization>purchasing organization</> correctly.

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

If you want to create a purchasing organization, maintain the settings
in MM Customizing (Purchasing) or consult your system administrator.
IF &DEVICE& = 'SCREEN'
<DS:TRAN.OMGL>Proceed</>
ENDIF

Error message extract from SAP system. Copyright SAP SE.