Sync somehow overloads server

Hello. I’m new to eM Client and I’m trying to setup my free account with the two allotted emails. One of them that is connected to gmail is working fine, but the other one seems to do something strange when I try to import folders from Thunderbird - it somehow sends all these files from my local drive on Thunderbird, to the server on, and then overloads the server and makes it so I can’t send or receive. I’ve tried deleting directly from the server, but when I log in the next day, they are all back, which leads me to believe it’s a migrating/synching problem. Any ideas? Thanks! Josh