There may be different reasons behind the email deletion and you can go through following possible reasons:
POP3/IMAP
If you’re using POP3 settings for your e-mail, when you retrieve new messages from a POP3 email account, the messages are deleted from the POP3 mail server and then saved on the computer that you are using. Because the message is no longer on the POP3 mail server, you can’t see it when you connect from another computer (unless you’ve told the e-mail client not to delete). If you’re using POP3 settings for your e-mail, when you retrieve new messages from a POP3 email account, the messages are deleted from the POP3 mail server and then saved on the computer that you are using. Because the message is no longer on the POP3 mail server, you can’t see it when you connect from another computer (unless you’ve told the e-mail client not to delete).
If your email account configured as IMAP and you are using same email account on different devices then you have to configure with IMAP on all devices other wise it will cause issues. Use POP or IMAP; do not mix the two. Doing so may cause emails deletion.
Hacking Attempts
Hackers create phishing emails through which they intend to steal your confidential information like passwords and bank account details. The phishing email might contain a link which on clicking will take you to a fake web page and asked for your information. Another way is the email might have an attachment and asks you to download it. As soon as you click on the download button and open the attachment, a malware gets installed on your system giving the hacker complete access to your device and data. Once hacker have you emails access, he can use your email account his own way. For more details, how email hacking works through Phishing/Malware attack “Click Here” or visit the following link.
https://faq.xperts.net.pk/how-email-hacking-works.html
We have also managed some beneficial “Email Safety Tips” to avoid this happening, please “Click Here” or visit the following link and read it carefully.
https://faq.xperts.net.pk/email-safety-tips.html
Mass Theft
More than 60% of people use the same username and password for all their accounts on different websites. Almost every website consider your given email address as username of that website. Hackers run programs that enter stolen username and password details on tens of thousands of sites until one hits. Then they have access to your accounts and credentials. If you use the same username and password on all accounts, that can leave you extremely vulnerable.
