Maximum number of connections exceeded while uploading messages

I open this topic even though I have seen that it has been covered before, but without having found a definitive solution.

I am using EM Client 10.1.4588 (with Pro license).

I moved some messages from an archive (generated via automatic archiving) to the /Inbox folder of an IMAP account. Since this time, whenever I synchronize this account, an upload of these messages is performed, but it fails because the server generates the error “Maximum number of connections from user+IP exceeded (mail_max_userip_connections=30)”. I have no other active connections except those of EM Client. It seems strange to me that it is using more than 30 connections. How is this possible? Is there any way to check the number of connections and limit the usage?

Thank you.