[horde] Horde can not login.

[Theewara Vorakosit]

    I can not login horde using imap. Both redhat 7.3 and 8.0. On red hat
7.3 it complains
 Warning: Certificate failure for localhost.localdomain: self signed
certificate:
/C=--/ST=SomeState/L=SomeCity/O=SomeOrganization/OU=SomeOrganizationalUnit/C
N=localhost.localdomain/Email=root at localhost.localdomain (errflg=2) in
Unknown on line 0

   In Red hat 8.0,
Jan 14 11:17:35 samsoft imapd[18444]: imap service init from 127.0.0.1
Jan 14 11:17:35 samsoft imapd[18444]: Command stream end of file, while
reading line user=??? host=UNKNOWN

    Would you please tell me how to solve this problem?
Thanks,
Theewara