I have been using Raspberry pi 3B as a wireless hotspot following this How to use your Raspberry Pi as a wireless access point. I think there is a limit to a number of devices that can be connected to the pi. I think it remember a certain number of devices that get connected to it but not sure how many? Anybody have any ideas? And how do I clear the history so that I can connect new devices. Already connected devices have no problem. Any help will be greatly appreciated.
To get a step forward I start this answer that we can improve step by step. Because lack of information I do some assumptions. You have made a stand alone access point without connections to any other devices by ethernet (eth0). Only other devices can connect but cannot go into the internet with the RasPi. You try to connect more than 20 devices to the access point. If you do not have modified the setup of the access point provided by the link then it is not possible that more than 20 devices can connect to the RasPi. The dhcp server
dnsmasq is configured in
/etc/dnsmasq.conf and set to:
From 192.168.0.11 to 192.168.0.30 are 20 ip addresses reserved to give to clients. You can change this for example by modifying the second ip address to 192.168.0.110. Now you will have 100 ip addresses reserved to give to clients. The highest possible ip address for this subnet is 192.168.0.254. Don't decrease the first ip address because then it will conflict with the static ip address 192.168.0.10 of your access point.