Varnish is not working with error 400 Bad Request

Issue

• Varnish service is up but is not working. From sudo varnishlog:

  *   << Request  >> 565789
  -   Begin          req 565788 rxreq
  -   Timestamp      Start: 1720502499.580800 0.000000 0.000000
  -   Timestamp      Req: 1720502499.580800 0.000000 0.000000
  -   HttpGarbage    "HEAD%00"
  -   RespProtocol   HTTP/1.1
  -   RespStatus     400
  -   RespReason     Bad Request
  -   ReqAcct        19 0 19 28 0 28
  -   End