I have googled long and hard, and spent much time trying to fix this problem, to no avail

I am asking whether some clever person can point me to some diagnostic tools to try to get to the basic problem. Win diags say all is OK (surprise!).

The issue is with one of my three win 10 comps (all are on build 10159). The other two can't access the problem one's shares using Explorer's network discovery or by using \\compname.

\\ipnumber works fine. Ping compname is fine. My 8.1 notebook can access the shares fine. 

The error I get is 'Windows can't access \\compname' - error id is 80070035. This error has been a nuisance for many years and no one seems to have a definitive answer as to why it occurs. It is the error you get trying to access shares on a comp in sleep mode. Actually, there have been many 'answers' but none that work for all and certainly not for me.

It's like a DNS error but for only this one comp! My Android phone (app Fing) has no trouble seeing all devices with their ip no. and name.

No 3rd party AV - just Defender.

Just tried two locally, only connected by switch - same result. Tried with firewall off - no go. 

Like I said, any diagnostics I can try?