I am using nginx version 1.16.1 as a forward proxy on a CentOS 7 server. Our order inventory server (ORDINV) connects through the nginx server (TAXPROXY) to request sales tax info from a cloud server. We are in test mode with this configuration. This all has been working well, except when they stop testing for a while, the taxproxy server stops working. The error log shows


2020/02/17 08:33:07 [info] 879#879: 42826 epoll_wait() reported that client prematurely closed connection, so upstream connection is closed too while SSL handshaking to upstream, client: xxx.xx.x.xx, server: taxproxy.umpublishing.org, request: "POST / HTTP/1.1", upstream: "https://yy.yyy.yyy.yy:443/services/CalculateTax70", host: "zzz.zzz.z.zz:80"

After a couple of these info there is [error] "peer closed connection in SSL handshake (104:Connection reset by peer) while SSL handshaking to upstream"

The nginx service is running, and if I issue a systemctl restart nginx, everything starts working again fine. Any ideas what might be wrong? Googling turned up several sites where people reported similar problems but no one had gotten an answer....

TIA~
Cindy