I will assume that you are using gmail.
It sounds like you are trying to archive your normal mail to a folder called archive on the email server and have exceeded your limit of space on the email server.
From EmClient move your mouse over the account and right click you should get a pulldown menu
Select properties
Select Quota and see what it says.
If exceeded then you will need to delete some email from the server.
You can use the emclient archiver which will copy email from the server to your PC reclaiming some space on the server. OR else buy more space on the server.
NOTE on gmail (they are sneaky) if you have archived to emclient go to folder “All Mail” and delete those items that you already archived to emclient offline folder. They (gmail) dont really purge things
Hopt this helps
Thank you for the reply, the first email account doesn’t give me the quota option at all, just General. And my account apparently has no storage quota.