Terraform fails in plan phase

My plan phase keeps failing during plan phase.

    You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.
If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your working directory. If you forget, other
commands will detect it and remind you to do so if necessary.
+ terraform plan '-out=plan.cache'
Error: Error locking state: Error acquiring the state lock: Unexpected HTTP response code 404
Terraform acquires a state lock to protect the state from being written
by multiple users at the same time. Please resolve the issue above and try
again. For most commands, you can disable locking with the "-lock=false"
flag, but this is not recommended.

Here is the ci file.

image: 
  name: registry.gitlab.com/gitlab-org/terraform-images/releases/0.14
  entrypoint:
    - '/usr/bin/env'
    - 'PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin'

variables:
  TF_ROOT: ${CI_PROJECT_DIR}
  TF_STATE_NAME: s3-bucket-tfstate
  TF_CACHE_KEY: s3-bucket-tfstate
  TF_ADDRESS: ${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/terraform/state/${CI_PROJECT_NAME}/s3-bucket-tfstate
  GITLAB_TF_ADDRESS: ${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/terraform/state/${CI_PROJECT_NAME}/s3-bucket-tfstate

cache:
  key: s3-resource
  paths:
    - ${TF_ROOT}/s3-resource/.terraform

before_script:
  - cd ${TF_ROOT}


stages:
  - s3_bucket_prepare_validate
  - s3_bucket_plan
  - s3_bucket_apply
#  - validate
#  - plan

s3_bucket_prepare_validate:
  stage: s3_bucket_prepare_validate
  script:
    - cd s3-resource
    - echo $GITLAB_TF_ADDRESS
    - gitlab-terraform init -backend-config="address=${GITLAB_TF_ADDRESS}" \
      -backend-config="lock_address=${GITLAB_TF_ADDRESS}/lock" \
      -backend-config="unlock_address=${GITLAB_TF_ADDRESS}/lock" \
      -backend-config="username=${GITLAB_USER_LOGIN}" \
      -backend-config="password=${GITLAB_TF_PASSWORD}" \
      -backend-config="lock_method=POST" \
      -backend-config="unlock_method=DELETE" \
      -backend-config="retry_wait_min=5" \
    - gitlab-terraform validate

s3_bucket_plan:
  stage: s3_bucket_plan
  script:
    - cd s3-resource
    - echo $GITLAB_TF_ADDRESS
    - gitlab-terraform plan 
    - gitlab-terraform plan-json
  dependencies:
    - s3_bucket_prepare_validate
  artifacts:
    paths:
      - ${TF_ROOT}/s3-resource/plan.cache
    reports:
      terraform: ${TF_ROOT}/s3-resource/plan.cache
      

s3_bucket_apply:
  stage: s3_bucket_apply
  script:
    - cd s3-resource
    - gitlab-terraform apply
  dependencies:
    - s3_bucket_plan
  when: manual
  only:
    - master

curl -H “private-token: xxxxxxx” https://gitlab.com/api/v4/projects/xxxxxx/terraform/state/terraform/s3-bucket-tfstate/lock
{“error”:“404 Not Found”}

Did you ever figure out how to fix this?

No, I have moved on to using s3 as state back end.