backend closed the channel unexpectedly

This is the last part of a "vacuum verbose analyze;":

NOTICE: --Relation pg_toast_17058--
NOTICE: Pages 2: Changed 0, reaped 0, Empty 0, New 0; Tup 9: Vac 0, Keep/VTL 0/0, Crash 0, UnUsed 0, MinLen 113, MaxLen 2034; Re-using: Free/Avai
l. Space 0/0; EndEmpty/Avail. Pages 0/0. CPU 0.00s/0.00u sec.
NOTICE: Index pg_toast_17058_idx: Pages 2; Tuples 9. CPU 0.00s/0.00u sec.
NOTICE: Analyzing...
pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.

This usually happens after some millions of rows are inserted into the database.
What can I do to avoid this error?

Greetings
Andreas