WAMPServer is configured to be a single seat developer tool for the AMP stack on a windows system.
As such and for the security of the complete beginner, WAMPServers Apache is configured to only accept connections from the PC that is running the Apache service.
If you want to connect to Apache from an IP other than that of the PC running WAMPServer, like your phone or another PC on your local network, you have to tell Apache that is allowed.
The simple solution for this is to use the wampmanager menus system :-
wampmanager -> Put Online
This will change the httpd.conf file from
# onlineoffline tag - don't remove
Require local
To
# onlineoffline tag - don't remove
Require all granted
Thus allowing any ip address in the universe to connect to your Apache web server. If you are sure that there is no external access to your local network this is reasonable solution.
If however you think that now or at some future time your network may allow access over port 80 from an external source, I prefer to be a little more specific when I change this parameter. So if you prefer you can
Edit the httpd.conf file, use the wampmanager menus to do this
wampmanager -> Apache -> httpd.conf
Then change this
# onlineoffline tag - don't remove
Require local
To
# onlineoffline tag - don't remove
Require local
Require ip 192.168.1
assuming that your local subnet starts with those 3 quartiles and that your phone is connected to your router via WiFi.
If your phone is using your suppliers network i.e. not your WiFi this will not work and you will have to Port Forward your router, but thats another question.