Apt update ERROR: The certificate of ‘linux-clients.seafile.com’ is not trusted

升级系统到debian11,用apt update想新安装seafile,报证书错.我搜去年9月也有人报过证书错 Unable to update seafile-cli,不知道是不是证书没更新?谢谢!

在下载证书的时候加个参数–no-check-certificate,可以把证书下载,但apt update的时候还是会报错:
Err:5 https://linux-clients.seafile.com/seafile-deb/bullseye stable InRelease
Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 443]
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

sudo apt-get --allow-unauthenticated update