Your dst-nat rule only takes when the packets come in on the pppoe-out1 interface - but they come in from your internal lan interface when you connect from the inner side.
There are several possibilities that could help you solve this problem:
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If you use your MikroTik as DNS (cache/forwarder), you could create a static IP address entry there for your DNS name pointing to the internal address (192.168.2.5).
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You could create some destination nat rule like
chain=dstnat in-interface=<your internal lan interface name> protocol=tcp dst-port=80 dst-address=<your webservers' public ip address> action=dst-nat to-addresses=192.168.2.5 to-ports=80
There are probably other ways that don’t come to my mind right now 
Best regards,
Christian Meis