Rahul Joshi:
I am using a trial version of Liferay DXP and sometimes I see this error-
Unable to connect to https://lcs-gateway.liferay.com. Please check your network connection settings and restart.
You have exceeded the developer license connection limit.
Could you please help me how I can ensure this error doesn't shows up again and again?
The first message indicates that either your server can't reach the provisioning LCS server or LCS is down. If it's showing repeatedly, most likely your firewall prohibits outbound communication of your server.
The second message indicates that your server, using the trial license, handles more requests/connections than included in the trial license. Contact Liferay sales to get a more permissive activation key if you need to access the server from many different places. Note that a few innocent google-bots and other indexers passing by might be enough to trigger this in case your server is reachable from the public internet.
