Pink Error "The page could not be loaded. [HTTP Code = 500] (APNX-1-4279-0

@gurdeeps - Where and when do you see this error? Have you checked both the App server and Engine logs and there is nothing in the logs? Please ensure that your engines are running fine.

Hi gurdeep could you please attach a screenshot of the error and tell us where exactly the error is coming

Is this error on the interface during design time?
If yes, Check if you have used underscore (_) on the interface.
I encountered a similar error when I accidentally placed an underscore in the value of document Image component.

Yeah , this error is on interface.

Which webserver are you using with Appian? If you are using IIS, you need to make a change to the way IIS returns error messages. Open the IIS Manager, and go to the Error Pages feature. Choose Edit Feature Settings, and ensure that 'Detailed Errors' is selected. This allows Appian to return detailed errors in the pink box message. You may have to restart IIS to see this change stick.

This KB article I wrote may assist with this:

forum.appian.com/.../kb-1126.html

Thanks everybody

Hi Gurdeep

Were you able to solve this error, we are getting the same error on 17.2 as well.

Gurdeep, There Can be multiple issue:
1. When you open the interface, is it open in Design View or Expression view? If it is opening in Expression view then there is something wrong with the code, to know the issue click on Design view, it will popup a message about the error.
2. If there is heavy data call on load of the interface, if it is there then try to make that call on process model level

Our Issue is not with the interface it happens sporadic with users while trying to negotiate between, tempo, or designer or admin console i was able to replicate the issue once. We will try to increase the thread count on our weblogic servers to see if that resolves the issue.