Why doesn't the iSCSI initiator on Windows Server 2012 see the target?

Question

NAS

Hello. There are 4 PCs with windows server 2012 and an iSCSI initiator, there is a Qnap nas storage with an iscsi target (server) raised on it. Moons are created and distributed to machines. Everything worked well, but on one of the machines the target object disappeared (empty). When trying to re-detect the target portal, the target writes: "Target device error". All 4 PCs have 2 network cards installed. From the problem machine pings from all network interfaces pass. Firewall is disabled. What could be the problem?
There is an error in the logs: iSCSI discovery via SendTargets failed, error code 0xefff0012 for the target portal