Sent mails deleted automatically

Sent mails deleted automatically

Hi,

I'm using Zoho mail for the past 3+ years. Recently i have noticed that my sent folder mails from the past 3 years has been deleted and contains only current month sent mails only. for eg:  as of today my sent folder contains mails sent from April 01, 2020 only. Where the other sent mails gone?  should i disabe anything ? i noticed last month only.

please help me to retrieve my lost mails.

. Thanks,
Ravi