No Model assigned to Service "***"; assign Model first

Hello experts,

     I try to add my service 'EQUIMAINT'  in /IWFND/MAINT_SERVICE

I get this message: No Model assigned to Service 'EQUIMAINT',assign Model first.

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But I have assigned model to my service as my picture

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and this is my service:

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How to do with this problem?

Thanks in advance!!!