Sent email disappeared from everywhere in iOS mail app gmail account
When I write an email or reply to an email on my gmail using the ‘mail’ app on my iPad and my iPhone, the message I just sent (after hearing the send sound) does not show up anywhere: not in the ‘sent’ box, nor ‘outbox’, nor in the ‘drafts’ or ‘trash’. Looked everywhere even logged into gmail via safari and looked in all folders there. And, it no longer shows up at the end of a string of messages if I’m responding to someone. I’ve made no changes to settings. It’s not the gmail app or the outlook app, it’s iOS own mail app, but the gmail account. I have now lost 3 emails in this way once sent, and no idea if it goes anywhere, not sure if it gets to the recipient.
How can this be fixed/prevented?
thank you
iPhone SE (3rd generation)