On Thu, May 09, 2019 at 02:43:36PM +0300, Andrei Susnea wrote: > Using openssl 1.0.2h I'm getting SSL_ERROR_SYSCALL while trying to > authenticate a certificate with the following SAN names configuration: The details of the certificate content are irrelevant. Something else changed. You should be looking at the correctness of your appliction code, and PCAP captures of the traffic to detect any network-layer issues. -- Viktor.