I have the same problem with SNMP, my dude agent cant reads SNMP data....(but ping OK).... ideas?
actually read the post and you will see that your problem is exactly the opposite. original poster said that SNMP works fine, but RouterOS doesn't work.
I have some dude agents in my network. When dude dude serwer gets information from routerboard using agent routeros tab is empty. But it can data from routerboard via snmp.
I assume you correctly have entered the "username/pass" of the RouterOS user in the Device settings, and have marked the "RouterOS" checkbox