不知何故，今天突然我的 Seafile 客户端抛出了这个错误。我不相信这是一个 seafile 问题，因为我的 openssl 抛出了完全相同的错误：
user@nb-user:~$ echo |openssl s_client -connect seafile.mydomain.ch:443
CONNECTED(00000003)
depth=1 C = IL, O = StartCom Ltd., OU = Secure Digital Certificate Signing, CN = StartCom Class 2 Primary Intermediate Server CA
verify error:num=20:unable to get local issuer certificate
verify return:0
---
Certificate chain
0 s:/description=5RygJ9fx8e2SBLzw/C=CH/ST=Thurgau/L=Frauenfeld/O=mydomain GmbH/CN=*.mydomain.ch/emailAddress=postmaster@mydomain.ch
i:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 2 Primary Intermediate Server CA
1 s:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 2 Primary Intermediate Server CA
i:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom …