Problem adding over 25 workstations/servers in asset management in service desk plus

Problem adding over 25 workstations/servers in asset management in service desk plus

I HAVE SERVICEDESK PLUS with 350 SERVER/WORKSTATION LICENSE   WHEN I TRY TO ADD MORE THAN 25 WORKSTATIONS IT DROPS THE LAST WORKSTATION AND WONT LET ME ADD MOVE THAN 25   

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