This is my first Mikrotik and I am learning - so please excuse me. I cannot connect remotely via public IP using winbox on a remote machine (at my office). I have no issues connecting via winbox at home. Internet connection via Charter with modem. I am sure it is a simple setting that I am missing. Thank you for the help.
Do you have any entries in “/ip firewall filter”?
Are you using the public ip to access the 751?
Public IP via IP Chicken. I will have to look when I get back home tonight as far as the IP filters. I will post what I have, if any. Thank you.
Check both the rules and the ip since it is dynamically assigned (dhcp?). If you have any questions, this is the place to ask. 
Yes (4) rules in IP, Firewall, Filter, rules (these rules assigned from defualt configuration - I did not add). In IP, Firewall, Filter Rules, In. Interface “Ether1-gateway” “action” is set to “drop”. Let me know if this needs to be set to another action . Thank you for the help!
In IP, Firewall, Filter Rules, In. Interface “Ether1-gateway” “action” is set to “drop”
That is the one that is blocking you.
Now you need to figure out how you want to access the router without disabling your router security. I use a rule like this. Change xx.xx.xx.xx/24 to the ip/subnet of the remote network at your office.
/ip firewall filter
add chain=input action=accept src-address=xx.xx.xx.xx/24
Move this rule above the ether1-gateway drop rule.
Thanks for the info. - yes a default firewall rule was blocking remote access. I will review your post for firewall settings.
You can limit it even more by only open up this port from your office subnet.
chain=input action=accept protocol=tcp src-address=xx.xx.xx.xx/24 dst-port=8291
That’s what I do. I close everything and then open just the ports I need from the source I need.