Mails subject to a filter are not showing up.

Hello, I'm currently using the thunderbird client to open a zoho mail account. I've set several filters (around 40) so that incoming emails are automatically redirected to the appropiate folder. If I click on the download/refresh icon (the little cloud with the downwards arrow), new email isn't received. On the bottom, a small message appears ("No new messages on the server" or something like this). You may think that that is precisely because I don't have new emails but if directly go into any of the folders and once again click on the download/refresh icon all of the emails that were supposed to go into that particular folder appear all at once (even mails that are 2 or 3 days old). Now every day I have to go into all of my 40 folders and click on the refresh button. I look forward to your help. Kind Regards.