This is caused by bug
https://bugzilla.redhat.com/show_bug.cgi?id=1836274
Solutions: Create a directory publicsuffix under /usr/share/
$ mkdir /usr/share/publicsuffix
go to publicsuffix directory
cd /usr/share/publicsuffix
Download the public_suffix_list.dat file
wget https://publicsuffix.org/list/public_suffix_list.dat
then restart dovecot and exim
$ systemctl restart exim
$ systemctl restart dovecot
that’s it