Error - Item doesn't exist or in inaccessible

[Alexwang]

Hello, I got the following error message from our WAB app. It didn't affect anything of the app, but just curious to know what caused this error and how to get rid of it?

[RobertScheitlin__GISP]

Alex,

  Unfortunately there is not enough info there to determine the source of the error.

[CherieSouthwick]

Alex, 

Did you ever find a solution to this issue? I am running into the same problem. All web apps in my Portal are throwing a "Item does not exist or is inaccessible" error. Their subsequent Web Maps are working properly.

Thanks,

Cherie