Hi @cablop,

Thank you very much for taking the time to leave a review here!

Do you have the latest version of the plugin? We fixed this issue in the 1.0.2 version. Please see here the changelog: https://github.com/WPChill/check-email/blob/master/changelog.txt and make sure that you update the plugin. If you have that version and it still happens, can you please open a support thread here:https://wordpress.org/support/plugin/check-email/ so we can investigate and help. Thank you!

Warm regards,
Beatrice.