Galaxy A6 tablet I could not understand why I received no further respons from emails I replied to. Searching found sent folder empty then looked in spam folder there I found the six previous replied to emails.
Just replied to another and its neither in sent or spam folders. Why does replied to emails end up either in spam or NO folder.
This email is Samsung built in cant be deleted only force stopped.

BobUK, February 2019

That's false positive from the SPAM filter.

For the message in the spam folder.
Mark them as non-spam/acceptable. That should cause them to be placed back in your inbox. It should also allow similar messages to stay in the inbox.

You may want to use another e-mail app. You can always install one of your choice.

Some times, e-mails can get blocked on the server before you ever see them. In this case, your only option option is to use another e-mail service.

Electro, August 2019