You may have reached your limit.
100 submissions are overall the total number of submissions that can be received through the form in the free version.
If 100 entry limit expires, the notification emails of the submissions are not generated. Still, not a single entry is lost. After the upgrade, the submissions held on our server become available on your Form Dashboard (Wix Editor page > double click on the form to open the Settings tab > View Entries).
So to continue receiving new submissions to your email address and to be able to see the new entries from your dashboard, please upgrade the app.