MySQL installation failed -gpg verification failed

Original error report
Public key for mysql-community-server-5.7.37-1.el7.x86_64.rpm is not installed
Failing package is: mysql-community-server-5.7.37-1.el7.x86_64
GPG Keys are configured as: file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql

Mysql Installation failed
operating system ：CentOS 7.6
Mysql edition ：mysql5.7
CentOS7.6 install mysql5.7 It's a mistake , Prompt that a package installation is not successful .

Reasons for failure
GPG For the source of the package key The verification of failed

terms of settlement
stay yum install Add after version --nogpgcheck, You can bypass GPG Verify successful installation . such as yum install mysql-community-server --nogpgcheck

doubt
But I don't understand the source of the package key Why didn't it pass the verification ？ It's strange here , I tried several 5.7 All versions of failed , Previous installations have been successful , You are welcome to comment and share if you understand the relevant information .

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