Should I Be Concerned About My Toddler S Fear Of Walking Outside?

My daughter is 14 months old. She started walking when she was 11.5 months. She is very confident of walking inside the house- she runs around all day. Now she has even started trying to climb beds and tables. However, she absolutely refuses to walk outside the house- on the building lobby/ building compound / grass/ play area etc. she seems terrified of those surfaces. Starts howling if put down- she is fine if carried or in the stroller but will just stand rooted to a spot and cry if put down. Should I be worried? How do I help her address this fear?