Iphone 8 & Iphone 10 not connecting to nrf51422(using BLE) having sdk 9.0 & soft devive s310

Dear Sir,

                 I am now using nrf51422 module (SRU532) for ANT+BLE application , i have used SDK_9.0.0_2e23562 and soft device s310_nrf51422_3.0.0. The problem i am facing is that the module is not connecting to the Iphone 8 ,Iphone 10 while using the BLE protocol. Plz suggest how to make iphone working with BLE ? Do i need to change the software what i am currently using for nrf51422 ( C:\Keil_v5\ARM\Device\Nordic\examples\multiprotocolnew\ble_ant_app_hrm\pca10028\s310\arm5_no_packs). Plz replay asp.

thaks & regards

sumanta