The report is a bit vague, but last time we solved a problem about 'socket errors' and upmpdcli, the problem was that IP Multicast was not enabled on the machine (multicast is used for UPnP discovery). More specifically, the one time we had a precise solution, this was a buildroot-created system, and the solution was to enable CONFIG_IP_MULTICAST
https://www.lesbonscomptes.com/upmpdcli/github-issues/upmpdcli-html/issue-108.html