Why it's not giving tick Mark as I completel the lesson

Hi Chetendra, This is a link to Teachable's article explaining this issue (the platform we're using at the moment). https://support.teachable.com/hc/en-us/articles/360004258771-Navigate-and-View-Course-Content Very soon (in the next few weeks), we'll introduce a new platform, which will be our own and such issues will be much easier and intuitive to resolve. Thanks for your patience. Best, Ned