PostgreSQL启动失败：pgAdmin4与psql连接报错求助

pgAdmin4启动失败报错 #

启动pgAdmin4时出现如下错误信息：

pgAdmin Runtime Environment
--------------------------------------------------------
Python Path: "/usr/pgadmin4/venv/bin/python3"
Runtime Config File: "/home/kredjo/.config/pgadmin/runtime_config.json"
pgAdmin Config File: "/usr/pgadmin4/web/config.py"
Webapp Path: "/usr/pgadmin4/web/pgAdmin4.py"
pgAdmin Command: "/usr/pgadmin4/venv/bin/python3 -s /usr/pgadmin4/web/pgAdmin4.py"
Environment: 
  - HOME: /home/kredjo
  - LANG: en_US.UTF-8
  - LOGNAME: kredjo
  - PATH: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/snap/bin
  - SHELL: /bin/bash
  - USER: kredjo
  - XDG_RUNTIME_DIR: /run/user/1000
  - GTK_MODULES: gail:atk-bridge
  - QT_ACCESSIBILITY: 1
  - XDG_DATA_DIRS: /usr/share/ubuntu:/usr/share/gnome:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop
  - DBUS_SESSION_BUS_ADDRESS: unix:path=/run/user/1000/bus
  - DEBUGINFOD_URLS: https://debuginfod.ubuntu.com 
  - DESKTOP_SESSION: ubuntu
  - GDMSESSION: ubuntu
  - GNOME_DESKTOP_SESSION_ID: this-is-deprecated
  - GNOME_SHELL_SESSION_MODE: ubuntu
  - GSM_SKIP_SSH_AGENT_WORKAROUND: true
  - IM_CONFIG_PHASE: 1
  - PWD: /home/kredjo
  - QT_IM_MODULE: ibus
  - SESSION_MANAGER: local/kredjo-Latitude-5320:@/tmp/.ICE-unix/2576,unix/kredjo-Latitude-5320:/tmp/.ICE-unix/2576
  - SHLVL: 0
  - SSH_AUTH_SOCK: /run/user/1000/keyring/ssh
  - USERNAME: kredjo
  - XDG_CONFIG_DIRS: /etc/xdg/xdg-ubuntu:/etc/xdg
  - XDG_CURRENT_DESKTOP: ubuntu:GNOME
  - XDG_MENU_PREFIX: gnome-
  - XDG_SESSION_CLASS: user
  - XDG_SESSION_DESKTOP: ubuntu
  - XDG_SESSION_TYPE: wayland
  - XMODIFIERS: @im=ibus
  - _: /usr/bin/gnome-session
  - MANAGERPID: 2333
  - INVOCATION_ID: fe3812bdff914eaba2e96e287611b3ca
  - JOURNAL_STREAM: 8:21777
  - SYSTEMD_EXEC_PID: 2630
  - MEMORY_PRESSURE_WATCH: /sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/session.slice/org.gnome.Shell@wayland.service/memory.pressure
  - MEMORY_PRESSURE_WRITE: c29tZSAyMDAwMDAgMjAwMDAwMAA=
  - GJS_DEBUG_OUTPUT: stderr
  - GJS_DEBUG_TOPICS: JS ERROR;JS LOG
  - GNOME_SETUP_DISPLAY: :1
  - DISPLAY: :0
  - XAUTHORITY: /run/user/1000/.mutter-Xwaylandauth.YLI3N2
  - WAYLAND_DISPLAY: wayland-0
  - GIO_LAUNCHED_DESKTOP_FILE: /usr/share/applications/pgadmin4.desktop
  - GIO_LAUNCHED_DESKTOP_FILE_PID: 356907
  - GDK_BACKEND: x11
  - NO_AT_BRIDGE: 1
  - PGADMIN_INT_PORT: 46809
  - PGADMIN_INT_KEY: c9442bd0-be29-433c-a548-cf5e767fea74
  - PGADMIN_SERVER_MODE: OFF
--------------------------------------------------------

Total spawn time to start the pgAdmin4 server: 0.004 Sec
Traceback (most recent call last):
  File "/usr/pgadmin4/web/pgAdmin4.py", line 48, in <module>
    import config
  File "/usr/pgadmin4/web/config.py", line 33, in <module>
    from pgadmin.utils import env, IS_WIN, fs_short_path

  File "/usr/pgadmin4/web/pgadmin/__init__.py", line 24, in <module>
    from flask import Flask, abort, request, current_app, session, url_for
ModuleNotFoundError: No module named 'flask'

psql终端连接报错 #

使用psql终端连接PostgreSQL时，出现如下错误：

psql: error: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: FATAL: database does not exist

已尝试过相关解决方案，但问题仍未解决，恳请协助。

内容的提问来源于stack exchange，提问作者Kredjo