Gmail e-mails missing in eM Client on Windows

Some Gmail e-mails are missing in my  eM Client 7.0 on Windows 10. The e-mails appear on all other devices (eg Android), and in the web Gmail interface. I have restarted eM Client and refreshed, but they are still missing.

Connectiivity is fine, as I have later e-mails.

This is very worrying, as I need to be 100% sure I am getting all my e-mails at all times. I would like to stay with eM Client, but I need a client which is reliable. Help please!