I'm stucked again. Please help me. Could you tell me where my mistake, please?
please, do not obfuscate hostnames, also postfix -n is needed and logfiles from postfix server.
I think you should try to use 127.0.0.1 as smtp server and without any encryptions to test.
On normal operations postfix and dovecot works from scratch. ( on advanced you need to do some modifications)
-- Eero, RHCE