You are only showing one??
Basically Destination NAT rule and firewall rule go hand in hand. One needs an allow rule in the forward chain so that all DST rules will work.
/ip firewall filter
add action=accept chain=forward comment=\
"Allow Port Forwarding" connection-nat-state=dstnat
Then you can make as many dst-nat rules as are required.
/ip firewall nat
add action=dst-nat chain=dstnat comment=MyPortFowardRule dst-port=8282 \
in-interface-list=WAN protocol=tcp to-addresses=10.21.1.46
(assumed protocol TCP as it was not detailed).
If you have multiple MT devices between the server and the internet make a diagram and annotate them with numbers.
For example if there is an MT in between, the only difference is the MT downstreap (its LANIP on the first MT) which is really also its WANIP would be the to-address LOL.
See diagrams will help.
I'd rather manage rats than software. Follow my advice at your own risk! (Sob & mkx forced me to write that!)