My $HOME on a server is in a Andrew file system, and the server runs kerberos.
I created a tmux session, wherein I ran a shell process. Then I detached it, and logged out, and after a while logged in again and reattach the tmux session. In the shell process in tmux, I found that I didn't have permission to access my (non-directory) files in $HOME. I checked my ticket and it didn't expire, and I renewed it by running krenew and still didn't have permission.
$ ls -l ls: cannot access README: Permission denied ls: cannot access setup.sh: Permission denied ls: cannot access setup.sh~: Permission denied total 14 drwxrwxr-x. 2 t 2048 Apr 6 21:48 bin drwxrwxr-x. 11 t 2048 Apr 24 18:16 data ??????????? ? ? ? ? ? README.md ??????????? ? ? ? ? ? setup.sh ??????????? ? ? ? ? ? setup.sh~ drwxrwxr-x. 2 t 2048 Apr 22 18:50 src Thanks!