As per your error, it seems replication slot has been dropped.
On Saturday, March 27, 2021, FOUTE K. Jaurès <jauresfoute(at)gmail(dot)com> wrote:
> Hello EveryOne,
>
> How can I solve Issue. ???
>
>
>
> *ERROR: could not start WAL streaming: ERROR: replication slot "XXX"
> does not exist2021-03-27 11:48:33.012 WAT [1090] LOG: background worker
> "logical replication worker" (PID 8458) exited with exit code 12021-03-27
> 11:48:38.019 WAT [8461] LOG: logical replication apply worker for
> subscription "XXX has started*
>
> All working fine a few days ago but this morning I have this issue.
>
> --
> Jaurès FOUTE
>