When accessing the terminal option within the cPanel UI, do you sometimes get the following error?
Error: The WebSocket handshake failed
Error: The connection to the server ended in failure at 3:56:05 PM. (ABORTED)
If you're running CloudLinux, one reason might be that the /bin/cagefs_eneter.proxied file no longer has the setuid bit set.
# stat /bin/cagefs_enter.proxied
Size: 11544 Blocks: 24 IO Block: 4096 regular file
Device: fd00h/64768d Inode: 6559052 Links: 1
Access: (0755/-rwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2020-09-14 23:19:10.980052726 +0200
Modify: 2020-09-02 09:53:43.000000000 +0200
Change: 2020-09-14 23:17:45.822484844 +0200
Permissions should be 4755. CloudLinux is actually tracking this issue in a case CAG-1082. The solution is to run the following
chmod u+s /bin/cagefs_enter.proxied
This should fix that and the terminal should work again.