Trying to transfer from Em Mail Client

I have been using Em Client and want to switch to Mailspring. Unfortunately, when I export emails from Em Mail client (Via .eml), I get errors on about 20% of when I try to import them to Mailspring. Am I missing something? Is there some other way?

I used Em client with pop3 so it didn’t save them or the structure on the server. So, I am also trying to setup the structure through IMAP with Mailspring so I never have to worry about it again.