Hi,
My wallet is not synching properly since 23 hours.
I am stuck on block 878240.
Any advise what I can do?
I am using newest wallet version 4.0.0.0-g
Thanks!
Check your firewall(s).
https://www.grc.com/shieldsup is a good place to start. Look for ports 696 and 6970 (they must be open).
As MagicStyle said, you might have been "peer blocked" and you'll have to delete the "peer.dat" file (with the wallet turned off).
If you're on windoze... well... check your antivirus firewall (if any), then your windows firewall, then your router firewall (and settings).