This is not a bug, from your log:
2020-05-18 15:46:09,595 can_retry: <class 'OSError'>, args=(10051, 'A socket operation was attempted to an unreachable network', None, 10051, None), errno=10051, code=10051, abort=10051
2020-05-18 15:46:09,596 tcp socket: 172.17.151.225:50626 <- 172.17.151.234:10000 closed
Traceback (most recent call last):
File "E:\Xpra\tags\v3.0.x\src/xpra/net/bytestreams.py", line 117, in untilConcludes
OSError: [WinError 10051] A socket operation was attempted to an unreachable network
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "E:\Xpra\tags\v3.0.x\src/xpra/net/protocol.py", line 648, in _io_thread_loop
File "E:\Xpra\tags\v3.0.x\src/xpra/net/protocol.py", line 727, in _read
File "E:\Xpra\tags\v3.0.x\src/xpra/net/bytestreams.py", line 329, in read
File "E:\Xpra\tags\v3.0.x\src/xpra/net/bytestreams.py", line 199, in _read
File "E:\Xpra\tags\v3.0.x\src/xpra/net/bytestreams.py", line 184, in untilConcludes
File "E:\Xpra\tags\v3.0.x\src/xpra/net/bytestreams.py", line 119, in untilConcludes
File "E:\Xpra\tags\v3.0.x\src/xpra/net/bytestreams.py", line 181, in can_retry
File "E:\Xpra\tags\v3.0.x\src/xpra/net/bytestreams.py", line 107, in can_retry
xpra.net.common.ConnectionClosedException: [WinError 10051] A socket operation was attempted to an unreachable network
The connection is closed, so the client exits.
The only thing we could do is to add an 'auto-reconnect' option, feel free to create a ticket for that.