The issue could be caused by corrupt files.
You can first try to just re-create the user details files. This is the extension or user configuration. If you have both configured you need to re-create both.
To replace and create a new user name file (pin codes), refer to topic:
Not all my users are listed - please add user on call listTo replace and create a new extension names file, refer to topic:
How do I import extensions from a file into TNG?Note: you do not have to move the tngdept file if you re-created the user details as it has blanked it already.
First try this and if you still cannot pull reports by user, then you will need to blank the transaction file - refer to topic :
How do I blank the TNG call details?