Maybe is on some kind of funny network with unusual protocols or mixed platforms where netbios and DNS can't work as efficiently as it should. I would test accessing the data using various accounts from another server or workstation via hostname/ip/etc and see if you get mixed or consistent results. That should indicate if there is a DNS problem lurking.
well u got a repair ticket with the NAS vendor hopefully he gets it resolved. i still think the problem is in the new HD he replaced maybe how the raid is configured i think is stripped all across some kind of config issue or a config issue in the router.
It's solved. What I did: Wiped my server 2012 (which was acting up, not saying it was causing net issues, but maybe, had been running since 2013) and installed 2012 R2. Factory reset on NAS. In this it may be pertinent to mention that the NAS has received many, many updates of its OS / FW but I had hardly ever made a Factory Reset. I am guessing it would help for the future to do a Factory Reset a bit more often, like once a year or something. At least not never which was about my case. I have yet to restore my network connections/cabling to previous state, with my switches, but there is no real need since I can have it all connected via my Router until a bigger recabling project I have planned gets done. In any case, the semaphore errors are gone.
Nice glad u got the issue fixed, maybe it was the NAS reset all u needed, this problem should be a sticky for people running NAS and run into semaphone-time out error.
I need to say that despite having SSH and HTTP access the NAS Technician was unable to come to any decisive conclusion, also, bear in mind, when you reset a NAS you risk loosing all Data, so you need a backup before. I can reset mine in two ways, the small "hole" in the rear of the box which will reset the accounts, but will not touch the data, and the Factory Reset function from within the NAS OS, that will kill all your data. Well worth considering.