eM Client is downloading old massages from the server on and on

My eM Client “decided” to constantly download old massages from the server (starting from March 13th). There is no rule with this. Sometimes only one or two mails are downloaded, sometimes all of them (around 100), sometimes genuinely new mails only. At the same time, MS Outlook (also installed on PC) does not have that problem, working with the same e-mail account (Pop3, PST files). Any idea? Best, Nemanja.

so if I understand this correctly you’re using POP3 for your email service? What version of eM Client are you using?
And are you seeing the old messages in the inbox or in a different folder?

Thank you,