Some sent emails are gone. Apple server problem?

Is this an Apple server problem? I have 4 devices on which I receive and send/receive my iCloud emails. An iMac, a MacBook pro, an iPad and my iPhone. All have the same Apple email account. Two days ago I noticed that all but one of my Sent emails from 4/14/26 until 10/2/26 are gone (Probably about 30 emails that I had sent and I know they were delivered). The hundreds of Sent emails prior to 4/14/26 are still in my Sent email box. I have looked (via Safari) at my iCloud account and those dates are gone from there as well. Yesterday, I send two emails and they appeared in my Sent email. I also looked on my iPhone and ALL of the sent emails were still on my phone. Today, the above dates are gone from my iPhone as well??? I have checked all my Settings on each device (I didn't change any email settings prior to this happening). My iCloud account is not out of memory. In my Mail inbox, when I click on the little arrow that shows I replied to a message I get "Error Mail was unable to find your reply to the message "XXXX". You may have deleted the message" (I have not deleted anything).