I create bucket, select B2 in aplication, enter account ID, master key - bucket is visible. Choose it and press continue.
wait about 2-3 minutes and get this
Failed to check the storage at b2://XXXX-XXXX-XXXXX: Head https://f002.backblazeb2.com/file/XXX-XXX-XXXX/config: read tcp XX.XX.XX.X:55151 to 206.190.215.16:443: wsarecv: An existing connection was forcibly closed by the remote host.
443 port is open and working.
Trying from another location - same error.
The Backblaze addresses may be blocked by your country: Cannot connect to BackBlaze B2 - connection reset by peer · Issue #509 · gilbertchen/duplicacy · GitHub
Yes, that is right 
These idiots have blocked an entire IP due to a single photo
I’m write to Backblaze but I don’t think they can do anything
go for a VPN, that helps in more ways than one.
The speed is very poor via VPN. Have to use Wasabi with stupid 90 day rule.
Backblaze support sent me this article with ip addresses
but i can’t understand how can i change it in duplicacy
Try different VPN provider. You should be getting the same speed, (or better, if your ISP likes to play with traffic shaping :))
payments for fast VPN + Backblaze may exceed the cost of 90 day rule in wasabi. I plan backup a lot of files - more than 2 Tb
Right, but you don’t have to keep paying for fast vpn. Make initial backup though it and cancel. Subsequent incremental backups can be slow. In fact, anecdotally, I’m running duplicacy under CPU throttler to drastically slow it down — I’d rather it takes 10 minutes to complete next hourly backup then do it under a minute but accompanied with fans flaring up, cpu, and network spike. There is no hurry with backup, especially so with vss; backup tool shall be in the background and invisible, using minimum resources.
This is common approach — Time Machine is configured to perform the same way.