Appian 18.3 , Showing error when clicked on Current user activity link

Question

The System Has Encountered an Error

HTTP Code: 500 APNX-1-4198-000 Error Evaluating UI Expression Expression evaluation error at function a!adminRouter: Error in a!forEach() expression during iteration 6: Expression evaluation error at function a!admin_getUsernameFromUuid_appian_internal [line 7]: The username _h-0000e183-a039-8000-6a00-011e94011e94_2 is not a valid user.

Joubin Izadi · Answer

To identify the user, see Mike Schmitt's answer from this link: https://community.appian.com/discussions/f/general/7297/can-we-pull-user-profile-or-username-from-uuid-present-in-the-log-files 
 
 I've copied his code below, which finds the user belonging to the UUID you're looking for, here referred to as ri!findUUID: 
 with(
 local!allUsers: getdistinctusers(
 cons!GROUP_CONTAINING_ALL_USERS
 ),
 local!allUUIDs: apply(
 fn!user(
 _,
 "uuid"
 ),
 local!allUsers
 ),
 local!lookupTable: joinarray(
 apply(
 fn!concat,
 merge(
 local!allUsers,
 repeat(
 length(
 local!allUsers
 ),
 " - "
 ),
 local!allUUIDs
 )
 ),
 char(10)
 ),
 local!foundUser: index(
 local!allUsers,
 wherecontains(
 ri!findUUID,
 local!allUUIDs
 )
 ),
 "Found: " & local!foundUser & char(10) & char(10) & "List:" & char(10) & local!lookupTable
)