package libgcrypt20:amd64 1.8.1-4ubuntu1 failed to install/upgrade: package libgcrypt20:amd64 is not ready for configuration cannot configure (current status 'half-installed')

[Wu Kwun Yu]

I find this error when I am installing Firefox.

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: libgcrypt20:amd64 1.8.1-4ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-23.25-generic 4.15.18
Uname: Linux 4.15.0-23-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
AptOrdering:
 libgcrypt20:amd64: Configure
 firefox:amd64: Remove
 NULL: ConfigurePending
Architecture: amd64
Date: Thu Jul 5 15:20:23 2018
Dependencies:
 gcc-8-base 8-20180414-1ubuntu2
 libc6 2.27-3ubuntu1
 libgcc1 1:8-20180414-1ubuntu2
 libgpg-error0 1.27-6
DpkgTerminalLog:
 dpkg: error processing package libgcrypt20:amd64 (--configure):
  package libgcrypt20:amd64 is not ready for configuration
  cannot configure (current status 'half-installed')
ErrorMessage: package libgcrypt20:amd64 is not ready for configuration cannot configure (current status 'half-installed')
InstallationDate: Installed on 2018-07-05 (0 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
Python3Details: /usr/bin/python3.6, Python 3.6.5, python3-minimal, 3.6.5-3
PythonDetails: /root/Error: command ['which', 'python'] failed with exit code 1:, Error: [Errno 2] No such file or directory: "/root/Error: command ['which', 'python'] failed with exit code 1:": "/root/Error: command ['which', 'python'] failed with exit code 1:", unpackaged
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.1
SourcePackage: libgcrypt20
Title: package libgcrypt20:amd64 1.8.1-4ubuntu1 failed to install/upgrade: package libgcrypt20:amd64 is not ready for configuration cannot configure (current status 'half-installed')
UpgradeStatus: No upgrade log present (probably fresh install)