Search endpoint(free/busy) stops working

Hi,
I've started receiving
{
"meta": {
"status_code": 403,
"status": "FORBIDDEN",
"message": "Insufficient permissions on account owner 53986. Requires: [basic_read]",
"more_info": {}
},
"data": {}
}

while trying to query free-busy endpoint,

My token works fine to me, while trying to query other endpoints, it is critical thing for us now, can someone, please, take a look at this?