yum/dnf install fail

I was using centOS8 and try to execute yum install -y gcc tcl and failed. The error shows it has some problem with signature check or something at rpm install process.The console log is like error: /var/cache/dnf/base-82351eca59c28538/packages/cpp-8.5.0-21.el8.x86_64.rpm: signature hdr data: BAD, no. of bytes(9088) out of range and Error: GPG check FAILED. I tried to upgrade my rpm installer and get same problem, and yum update didn't work either. I tried to use --nogpgcheck, it still didn't work.