Internet is working on my PC but in n8n "connection lost" is written ,so how to solve this issue?

Hi @Amina1 Welcome to the community!

Can you share more information regarding your n8n instance?
Although this mostly happens due to not well configured n8n instance or unstable connection, i recommend restarting your n8n instance and things should be working just fine, if they don’t consider setting the webhook URL and then restarting your n8n instance.

I would also recommend updating your n8n instance to the latest version 2.x which have less unstable issues.