Can someone guide me? The letter "M" is hollow, no solid inside. Is there a substitute?

It is an error on the part of the font author/designer. The error affects both M and m. I did not check the other letters. It is easy to fix but it has to be done by the font author/designer. Please send him a private message at https://www.dafont.com/pm/post.php?user=880017 or you can send him an email at the email address shown on this page https://www.dafont.com/profile.php?user=880017

I contacted the author who thought the problem had been fixed, so he sent me the corrected version. Thank you for your concern. Have a nice day!