Invalid input syntax for timestamp error with Postgres Copy command

I am trying to load data in Postgres through COPY command in a SQL file

COPY   (, ,  etc etc) FROM stdin;

1    test1   test2   to_timestamp(1592818988000)

But I am getting this below error: > psql:/Users/sanupin/load.sql:1045: ERROR: invalid input syntax for > type timestamp: "to_timestamp(1641278614000)" CONTEXT: COPY > cstone_storage, line 1, column last_loaded: > "to_timestamp(1641278614000)" Any idea what could be the problem? I know I have to convert the millisecond to second (div by 1000) on the epoch number, but not sure how else to proceed.