To a view the user access logs on a Dream Machine Pro, simply connect to the device via SSH, then you can enter the command...

sudo tail -n 100 /mnt/data_ext/unifi-os/unifi-protect/logs/clientnotify.log

Change the number after the -n to select how many lines to search. If you want to view the logs in a more readable format and search for a specific user, simply add the text "| grep "USERS_NAME", like this...

sudo tail -n 100 /mnt/data_ext/unifi-os/unifi-protect/logs/clientnotify.log | grep "USERS_NAME"