Reload failed because retrieve_conf encountered an error: 1

Hello
I tried to make some changed to an extension via user manager (I was setting up the UCP). When I press the “Apply Config” button I get an error. The main dashboard displays "Reload failed because retrieve_conf encountered an error: 1"
What can I do to resolve this issue? I’ve rebooted FreePBX machine with no improvement. Thanks in advance for your responces.

Update:
I made an entry to the phone book which required I “Apply Config”. This was successful and the “Apply Config” button went away. Could the moderator please close this ticket.
Thanks