How to dump and restore correctly a postgresql db from docker

I stuck with this error when trying to backup and restore my database from a docker django app environment :

I first did this command to backup my whole DB

docker exec -t project_final-db-1 pg_dumpall -c -U fred2020 > ./db/dump.sql

And then trying to restory with this command

cat dump.sql | docker exec -i --user fred2020 catsitting-db-1 psql -U fred2020 -d postgres 

I have two containers, one for my django app named catsitting-web-1 and one for my postgresql named catsitting-db-1.

I don’t understand why it gaves me that error, my db user is the same that I specified on the Dockerfile.

Any clue ?
For purpose help, here is my docker files configuration :

Dockerfile

FROM python:3.9
ENV PYTHONUNBUFFERED=1
WORKDIR /code
COPY requirements.txt /code/
RUN pip install -r requirements.txt
RUN pip install Pillow
COPY . /code/

docker-compose.yml

version: "3.9"
    
services:
    db:
    image: postgres
    environment:
        - POSTGRES_DB=postgres
        - POSTGRES_USER=fred2020
        - POSTGRES_PASSWORD=p*******DD
    expose:
        - "5432"
    ports:
        - 5432:5432
    web:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
        - .:/code
    ports:
        - "8000:8000"
    depends_on:
        - db

requirements.txt

Django>=3.0,<4.0
psycopg2-binary>=2.8
Pillow==8.1.0

And that’s my process to migrate from laptop1 to laptop2 :

Installation
Run a command line go into a root directory and run:

git clone https://github.com/XXXXXXXXXXXXXXXX

In the command line go into the root directory:

cd catsitting

In the same command line window, run:

docker-compose build --no-cache

In the command line window you need first to migrate the database for Django, run :

docker-compose run web python manage.py migrate

In the command line window then you need to apply the migrations, run :

docker-compose run web python manage.py makemigrations

In the command line window then you need to import database, run :

cat dump.sql | docker exec -i --user fred2020 catsitting-db-1 psql -U fred2020 -d postgres 

(for dumping my DB I used docker exec -t project_final-db-1 pg_dumpall -c -U fred2020 > ./db/dump.sql)

You can now run:

docker-compose up

Is there something I get wrong ?