HTTP Code: 500 error while editing interface

Question

Has anyone else encountered an HTTP Code: 500 error while editing an Interface containing only a gridRowLayout? 
 I have seen this occur several times across multiple different applications. All applications were local installs. 
 The interface object becomes no longer accessible from the application in /design. The only solution I've found is deleting the object and remaking it.

aloks0189 · Answer

Hi alexandral I believe, if you are on cloud premises then please raise a support ticket to Appian support but if you're on local instance premises then try restarting the application server, this should be able to resolve it.

Dastagiri Dudekula · Answer

alexandral I just made an experiment, don't insert a!dropdownField . Add a!dropdownField() . 
 Root cause is that when you add a component name (here a!dropdownField) without brackets this will cause this pink error with HTTP Code : 500. 
 Solution when you type the component name either select the component from the suggestion or type the name with brackets. 
 Look at the attachment I have reproduced the error with a!textField.

Dastagiri Dudekula · Answer

Please follow community.appian.com/.../61364