Getting 403 error

Today suddenly we are getting the following error which I dont quite understand. Its not the data base I am trying to access directly to get restrictions. It just simply the app trying to list the items. All was working and never experienced such error at this.
I am having two question:
1- What is the cause fo the error
2- how can it be prevented?

Unhandled Rejection (Error): Request failed (GET IP address is not allowed to access this resource (status 403)

The problem is some how fixed. Seemed it has been conflict of Access Ip’s.