404 page Not Found with PrefixPath File Provider

Hi all, i am new in traefik

i want to proxy my api service with PathPrefix but always getting 404 not found.
https://mydomain.com/v1 to myapi.mydomain.com/v1

Traefik version 2.7

services:
  traefik:
    image: traefik:v2.7
    ports:
      # Listen on port 80, default for HTTP, necessary to redirect to HTTPS
#      - 80:80
      # Listen on port 443, default for HTTPS
#      - 443:443
      - target: 80
        published: 80
        mode: host
      - target: 443
        published: 443
        mode: host
    deploy:
      placement:
        constraints:
          # Make the traefik service run only on the node with this label
          # as the node with it has the volume for the certificates
          - node.labels.traefik-public.traefik-public-certificates == true
      labels:
        # Enable Traefik for this service, to make it available in the public network
        - traefik.enable=true
        # Use the traefik-public network (declared below)
        - traefik.docker.network=traefik-public
        # Use the custom label "traefik.constraint-label=traefik-public"
        # This public Traefik will only use services with this label
        # That way you can add other internal Traefik instances per stack if needed
        - traefik.constraint-label=traefik-public
        # admin-auth middleware with HTTP Basic auth
        # Using the environment variables USERNAME and HASHED_PASSWORD
        #- traefik.http.middlewares.admin-auth.basicauth.users=admin:xxx
        - traefik.http.middlewares.admin-auth.basicauth.users=admin:xx
        # https-redirect middleware to redirect HTTP to HTTPS
        # It can be re-used by other stacks in other Docker Compose files
        - traefik.http.middlewares.https-redirect.redirectscheme.scheme=https
        - traefik.http.middlewares.https-redirect.redirectscheme.permanent=true
        # traefik-http set up only to use the middleware to redirect to https
        # Uses the environment variable DOMAIN
        - traefik.http.routers.traefik-public-http.rule=Host(`traefik.university.com`)
        - traefik.http.routers.traefik-public-http.entrypoints=http
        - traefik.http.routers.traefik-public-http.middlewares=https-redirect
        # traefik-https the actual router using HTTPS
        # Uses the environment variable DOMAIN
        - traefik.http.routers.traefik-public-https.rule=Host(`traefik.myuniversity.com`)
        - traefik.http.routers.traefik-public-https.entrypoints=https
        - traefik.http.routers.traefik-public-https.tls=true
        # Use the special Traefik service api@internal with the web UI/Dashboard
        - traefik.http.routers.traefik-public-https.service=api@internal
        # Use the "le" (Let's Encrypt) resolver created below
        - traefik.http.routers.traefik-public-https.tls.certresolver=le
        # Enable HTTP Basic auth, using the middleware created above
        - traefik.http.routers.traefik-public-https.middlewares=admin-auth
        # Define the port inside of the Docker service to use
        - traefik.http.services.traefik-public.loadbalancer.server.port=8080
    volumes:
      # Add Docker as a mounted volume, so that Traefik can read the labels of other services
      - /var/run/docker.sock:/var/run/docker.sock:ro
      # Mount the volume to store the certificates
      - traefik-public-certificates:/certificates
      # localtime
      - /etc/localtime:/etc/localtime
      # configuration file
      - /home/centos/traefik/config:/config
    command:
      # Enable Docker in Traefik, so that it reads labels from Docker services
      - --providers.docker
      # Add a constraint to only use services with the label "traefik.constraint-label=traefik-public"
      - --providers.docker.constraints=Label(`traefik.constraint-label`, `traefik-public`)
      # Do not expose all Docker services, only the ones explicitly exposed
      - --providers.docker.exposedbydefault=false
      # Enable Docker Swarm mode
      - --providers.docker.swarmmode
      - --providers.file.directory=/config
      - --providers.file.watch=true
      - --serversTransport.insecureSkipVerify=true
      # Create an entrypoint "http" listening on port 80
      - --entrypoints.http.address=:80
      # Create an entrypoint "https" listening on port 443
      - --entrypoints.https.address=:443
      # Create the certificate resolver "le" for Let's Encrypt, uses the environment variable EMAIL
      - --certificatesresolvers.le.acme.email=user@university.com
      # Store the Let's Encrypt certificates in the mounted volume
      - --certificatesresolvers.le.acme.storage=/certificates/acme.json
      # Use the TLS Challenge for Let's Encrypt
      - --certificatesresolvers.le.acme.tlschallenge=true
      # Enable the access log, with HTTP requests
      - --accesslog
      # Enable the Traefik log, for configurations and errors
      - --log
      # Enable the Dashboard and API
      - --api
    networks:
      # Use the public network created to be shared between Traefik and
      # any other service that needs to be publicly available with HTTPS
      - traefik-public

volumes:
  # Create a volume to store the certificates, there is a constraint to make sure
  # Traefik is always deployed to the same Docker node with the same volume containing
  # the HTTPS certificates
  traefik-public-certificates:

networks:
  # Use the previously created public network "traefik-public", shared with other
  # services that need to be publicly available via this Traefik
  traefik-public:
    external: true

My Dynamic file

http:
  routers:
    myservice-v1:
      entryPoints:
        - https
        - http
      rule: "(Host(`mydomain.com`) && PathPrefix(`/v1`))"
      middlewares:
        - default-headers
        - add-v1
      service: backend-v1-service
 middlewares:
    add-v1:
      addPrefix:
        prefix: "/v1"
 services:
    backend-v1-service:
      loadBalancer:
        passHostHeader: true
        servers:
          - url: "https://myapi.mydomain.com/"

My traefik log

192.168.200.15 - - [07/Jun/2022:02:49:12 +0000] "GET /v1 HTTP/2.0" 404 19 "-" "-" 922 "-" "-" 0ms
192.168.200.15 - - [07/Jun/2022:02:49:13 +0000] "GET /v1 HTTP/2.0" 404 19 "-" "-" 923 "-" "-" 0ms
192.168.200.15 - - [07/Jun/2022:02:49:13 +0000] "GET /v1 HTTP/2.0" 404 19 "-" "-" 925 "-" "-" 0ms
192.168.200.15 - - [07/Jun/2022:02:49:17 +0000] "GET /v1 HTTP/2.0" 404 19 "-" "-" 929 "-" "-" 0ms
192.168.200.15 - - [07/Jun/2022:02:56:18 +0000] "GET /v1 HTTP/2.0" 404 19 "-" "-" 963 "-" "-" 0ms

from the traefik log above router host rule with PathPrefix is never getting hit to backend service .
any advice ?

i also check backend service log there is no log traefik server accessing backend service.