After upgrade I see in "The Dude" that services "partyally down". It CPU. So what the problem? It seems to me router is working fine. But I worry about other routers. Should I upgrade them to 5.21? How I can get rid off the CPU problem?

is SNMP turned on in RouterOS? if not, CPU status will not be read, and cause the mentioned error

I turned on SNMP, but no results...

in Dude, double click the device, go to Services and click Discover. It should show you available services that you can monitor. It should also fix CPU

Should I open SNMP UDP-161 from external (in the firewall)? I try to monitor from outside.

yes, of course, your last firewall rule drops everything that is not allowed above

rule 9 allow snmp to router from outside.

disable all rules, and you will see if firewall is the problem or not

Thank's. I tried to run The Dude from inside network and it'k ok.