Cloud sync fails to sync with error "mount error(16): Device or resource busy"

[2022-12-07T06:56:50.383] [INFO] [MASTER] [0] [717730] Executing command { command: "mount -t cifs //10.xx.xx.157/'testshr1' mnt/638db135ddddd0cf6c5fa47d/4493c5cb-e388-4dd5-be7f-d5875d3b1698_src -o domain=naslab,vers=2.1,file_mode=0666,dir_mode=0666,iocharset=utf8,mapchars,mfsymlinks", timeout: 20000 }
[2022-12-07T06:56:50.384] [ERROR] [MASTER] [0] [717730] Failed to execute command Error: Command failed: mount -t cifs //10.xx.xx.157/'testshr1' mnt/638db135ddddd0cf6c5fa47d/4493c5cb-e388-4dd5-be7f-d5875d3b1698_src -o domain=naslab,vers=2.1,file_mode=0666,dir_mode=0666,iocharset=utf8,mapchars,mfsymlinks
mount error(16): Device or resource busy
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log messages (dmesg)

    at ChildProcess.exithandler (child_process.js:383:12)
    at ChildProcess.emit (events.js:400:28)
    at ChildProcess.emit (domain.js:475:12)
    at maybeClose (internal/child_process.js:1088:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:296:5) {
  killed: false,
  code: 32,
  signal: null,
  cmd: "mount -t cifs //10.xx.xx.157/'testshr1' mnt/638db135ddddd0cf6c5fa47d/4493c5cb-e388-4dd5-be7f-d5875d3b1698_src -o domain=naslab,vers=2.1,file_mode=0666,dir_mode=0666,iocharset=utf8,mapchars,mfsymlinks"
}
[2022-12-07T06:56:50.385] [INFO] [MASTER] [0] [717730] SEND MESSAGE: {"message":{"step":"INITIALIZE","relationshipId":"638db135ddddd0cf6c5fa47d","status":"FAILED","reason":"Failed to mount source: mount error(16): Device or resource busy\nRefer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log messages (dmesg)\n","source":{"cifs":{"host":"10.xx.xx.157","share":"/testshr1","version":"2.1","provider":"cifs"}},"target":{"cifs":{"host":"10.xx.xx.102","share":"/test_vol1","version":"2.1","provider":"cifs","path":"new_share"}},

• dmesg log  :