Hi Mohsen,
Check the below default authorization is there or not for the logged in user.
And check the Authorization objects S_DEVELOP,S_PB_CHIP and /UI2/CHIP are assigned or not.Give Full authorization for these objects (value=*)
If not solved Execute the task SAP_FIORI_LAUNCHPAD_INIT_SETUP from STC01 t-code.
Still no joy, please share the front end error log.
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Thanks & Regards
Abdul Basha Shaik