Something went wrong during merge pre-receive hook


when i use online merge, i got an error about merge.
Merge still running, but merge reques does not close.

if i do merge locally. everything is ok.

i found some logs below.
it seems like custom hooks error, but i do not add any custom hooks config

/var/log/gitlab/gitaly/current

{
  "correlation_id": "01FKHYX0GNMFW7G1G0433SSW1C",
  "error": "executing custom hooks: exit status 127",
  "grpc.meta.auth_version": "v2",
  "grpc.meta.client_name": "gitlab-sidekiq",
  "grpc.meta.deadline_type": "unknown",
  "grpc.meta.method_type": "bidi_stream",
  "grpc.method": "UserMergeBranch",
  "grpc.request.deadline": "2021-11-03T17:53:51.493",
  "grpc.request.fullMethod": "/gitaly.OperationService/UserMergeBranch",
  "grpc.request.glProjectPath": "mygrouop/myproject",
  "grpc.request.glRepository": "project-235",
  "grpc.request.repoPath": "@hashed/0a/2d/0a2d643bfd24a028cd236e76575d828424ccffbfa47392bd09d8ca9dc85e2f8d.git",
  "grpc.request.repoStorage": "default",
  "grpc.service": "gitaly.OperationService",
  "grpc.start_time": "2021-11-03T11:53:51.493",
  "level": "warning",
  "msg": "stopping transaction because post-receive hook failed",
  "peer.address": "@",
  "pid": 16250,
  "remote_ip": "10.10.50.52",
  "span.kind": "server",
  "system": "grpc",
  "time": "2021-11-03T03:53:51.640Z",
  "username": "fox"
}

/var/log/gitlab/gitlab-rails/application_json.log

{
  "severity": "ERROR",
  "time": "2021-11-03T05:48:32.726Z",
  "correlation_id": "01FKJ5F07JXS11AF98M9X8DJ1Z",
  "message": "MergeService ERROR: mygroup/myproject!160 - Something went wrong during merge pre-receive hook."
}

Does anyone have suggestions?

gitlab version: gitlab-ce-14.4.1