as @andreas-doehler stated, tho nossl-switch is missing. Funny enough, it probably never ever worked. Fortunately I cannot check any mikrotik with plain http api, so please @lucian do me a favor and run:
/omd/sites/checkmk/local/share/check_mk/agents/special/agent_mikrotik -u XXX -p XXX -n -c 8728 -i '10.10.10.11'
Mind the -n switch. If this produces some output that are not errors I can provide you a fix for that issue.
ttr