netbox RB911G-5HPacD disappeared from network

hello ,
i am new to mikrotik i am using netbox RB911G-5HPacD on bridge mode for AP , i am facing problem my netbox disappeared from network repeatedly and user not able to use internet
my netbox on bridge mode , lan ip use 10.0.0.70 , bridge port lan and wan channel 20 frequency auto i have done many changes but not efface
i am using in network 2 netbox ,1 basebox , 2 rocket m5 one mikrotik main router , all device working good that one not working , plz guide me any help where i am doing wrong
sorry for my bed english

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