Because of LPU overload makes FTP/Telnet/TFTP service interrupted on S9700

1. Because we can ping directly from another S9700, it proves the network ok.
2. We delete the configuration and re-configure it. Test still not work.
3. Login device and check something
On S9700, it can ftp/telnet itself. it proves ftp/telnet modules works fine.
<S9706-Edge>ftp 192.168.78.230
Trying 192.168.78.230 ...
Press CTRL+K to abort
Connected to 192.168.78.230.
220 FTP service ready.
User(192.168.78.230:(none)):ftpuser
331 Password required for ftpuser.
Enter password:

Check routes and it is here
[S9706-Edge]disp ip routing-table  192.168.78.230
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Table : Public
Summary Count : 1
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

192.168.78.230/32  Direct  0    0           D   127.0.0.1       Vlanif2

Check FIB tables and found there is no table.
[S9706-Edge-diagnose]dis fib 2  192.168.78.230 verbose
  Route Entry Count: 0
[S9706-Edge-diagnose]
[S9706-Edge-diagnose]dis fib 4  192.168.78.230 verbose
  Route Entry Count: 0
[S9706-Edge-diagnose]

We found the problem. There is no fib table on LPU board. Packets cannot be forward correctly. After futher check, we found S97 works overload before.
[S9706-Edge-diagnose]dis fib  overload  state  slot  2
  Overload mode:
    Overload forward mode.
  Overload state:
    Overload forward state.

4. Solution is that recover overload status and refresh fib table.
[S9706-Edge]recover fib overload  forward slot  2
Warning: Succeeded in recovering, please run refresh command to update FIB.
[S9706-Edge]refresh fib  slot 2

And test it works.

Root Cause
1. Network issue
2. Configuration issue
3. Device issueSolution
Suggestions
None