I have deployed my personal portfolio which written in flutter and has linkedin,github links and when i try to open that link on deployed portfolio it showing an error that “page not found”
whats the name of your site? If you are experiencing the page not found area check this out. This is the best place to start for “Page Not Found” issues.
If you are still seeing issues after following the troubleshooting steps in there, please check out this Support Guide as well. It outlines all of our build and deploy resources and will get you on the right track 
If none of the above resources help, please write back with your site name and what steps you have tried and we can look into this further!