There are several possible reasons for this situation

1) Problems with git version

2) The system time is wrong

1) For the first case, use this command to see the GIT version.

git –version

Most of the time, just uninstall the original GIT and re install a newer version. （ https://www.kernel.org/pub/software/scm/git/ perhaps https://github.com/git/git/releases ）

2) For the second case, just modify the system time directly.

Use commands to modify, such as:

date -s “25 MAY 2019 17:30:00”

Manual modification is also possible.