Webui bad gateway

Hi,

Whenever I restart WebUI services its getting stuck on login page & giving error as “bad gateway”

I am able to solve it if I just rename the sites folder but its kind of repeated activity, anyone having suggestion on this please.

Below are the logs from webui log file-

    Mon, 02 Dec 2019 13:08:44 GMT bf:appmonitor:debug For Autopatch app, nodeArgs: 
    Mon, 02 Dec 2019 13:08:44 GMT bf:appmonitor:debug [ '--expose_gc', '--max-old-space-size=8192' ]
    Mon, 02 Dec 2019 13:08:44 GMT bf:appmonitor:error Failed to create app from E:\Program Files (x86)\BigFix Enterprise\BES WebUI\WebUI\sites\WebUI Permissions and Preferences_12580_3_1558126460\pps-app: Error: ENOENT: no such file or directory, open 'E:\Program Files (x86)\BigFix Enterprise\BES WebUI\WebUI\sites\WebUI Permissions and Preferences_12580_3_1558126460\pps-app\package.json'
    Mon, 02 Dec 2019 13:08:44 GMT bf:appmonitor:error Failed to start apps: TypeError: Cannot read property 'name' of null