Restic sftp: "Permission denied" (SSH_FX_PERMISSION_DENIED)

I'm trying to use backup my data with restic over ssh from my main machine macos to the raspberry pi 3 with ssd drive. ssh works fine but when I'm trying to use sftp with restic I get this error:

Fatal: create repository at sftp:hostname@ipaddress:/mnt failed: sftp: "Permission denied" (SSH_FX_PERMISSION_DENIED)

command I'm trying to exe: restic -r sftp:hostname@ipaddress:/mnt init

How to fix this?