Hei,
I've got three RB4011 that won't update ddns in IP/CLOUD. The config is correct, i've tried it on other routers. They run on version 6 long-term
Also ran a packet capture on UDP/15252 and traffic goes out and gets answered. But no update of time not device cloud ddns name

The thing is/might be that their serial number no longer matches the mac adress.

(all digits are replaced with '0')
HD00000M0SV
HD000F0GK0N
HD000DKQC0P

Anyone with the same experience ??

The thing is/might be that their serial number no longer matches the mac adress.

Serial numbers never matched the MAC.

you're right. but at least the looked like a mac address

I never see (on MikroTik products from 2007+) a serial number that match the MAC address, and the DNS name can contain any ascii-7bit letters and numbers.

(probably can be forced on x86/64 and CHR version, setting on the VM interface one MAC address that resemble the x86/64 Software-ID or the CHR System-ID)