Mikrotik RB750 can't access Internet

Rather than copy and paste the information I have posted elsewhere, can anyone here suggest what might be causing the problem I have described in this forum:

http://forums.whirlpool.net.au/forum-replies.cfm?t=2075671

Do you have default route in your routing table?

I’m not sure where that’s specified. In the web configurator, there’s a “Routes” entry under “IP”, and also a separate “Routing” entry with subheadings, such as BGP.

in winbox: new terminal-> ip route export

paste routing table here…

Did you mean ip route print? Here's that.

[admin@MikroTik] /ip route> print
Flags: X - disabled, A - active, D - dynamic,
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme,
B - blackhole, U - unreachable, P - prohibit

DST-ADDRESS PREF-SRC GATEWAY DISTANCE

0 ADS 0.0.0.0/0 10.20.21.18 1
1 ADC 10.20.21.18/32 60.240.73.144 PPP1 0
2 ADC 192.168.88.0/24 192.168.88.1 ether2-master-l... 0

Problem solved, thanks to the Whirlpool thread I posted in the OP. I was using the Ethernet gateway interface in the rules, instead of the PPPoE client.