Sent emails are not in Sent folder

I am unsure what a third party client is. I use my iPhone and iPad to send emails using my Comcast account. This has happened before where my Sent emails disappear for some unknown reason. I have not heard from anyone from Xfinity yet pertaining to this issue. Thank you.

Hey there Jgreb608, just to clarify a 3rd party email client would be like Mail for Apple (usually a blue suqare with the white envelope), Mail for Android, Outlook, Thunderbird, or different programs that are not directly Xfinity, but allow you to access your email from us. If you are using an iPhone or iPad often times customers are using the Mail App for Apple. If you are not seeing all of your emails. It may be a situation where you would need to log into Xfinity.com and go to your email settings. There is an option to sync your mail across the Xfinity website and the third party apps. Here is a link that may be of assistance: https://www.xfinity.com/support/articles/update-your-xfinity-email-settings.