Install libencode-imaputf7-perl by entering the following commands in the terminal:
sudo apt update sudo apt install libencode-imaputf7-perl
Description:
modification of UTF-7 encoding for IMAP
IMAP mailbox names are encoded in a modified UTF-7 when names contains international characters outside of the printable ASCII range. The modified UTF-7 encoding is defined in RFC2060 (section 5.1.3).
Homepage: http://search.cpan.org/dist/Encode-IMAPUTF7/
Version: 1.05-2
Section: universe/perl