Very slow mail download/notification with dovecot 2.3.7 and Thunderbird​

Hi! I know that there are many results if I search for "dovecot thunderbird very slow" on Google but none of them helped me with my problem. :(  (I already posted this on February 2020, but forgot to answer. O.o) I am running Ubuntu 20.04 (4GB RAM, 40GB HDD with EXT4) server with the following so

Very slow mail download/notification with dovecot 2.2.33 and Thunderbird

Hi! I know that there are many results if I search for "dovecot thunderbird very slow" on Google but none of them helped me with my problem. :( I am running Ubuntu 18.04 (4GB RAM, 40GB HDD with EXT4) with the following software: - Dovecot 2.2.33 All accounts are using Maildir Sieve fil