Sorry, your English is a bit difficult to read for me. Are you asking a) why other people's messages are not visible to you, or b) why your messages are not visible to other people?
If a), then perhaps you have them ignored (get a list with /ignore -l (letter L, not numeral 1)). Or perhaps they are appearing in a different window - check the switchbar (probably above the main screen) which has all the windows listed.
If b), then perhaps you're running a script which is blocking them (for some unknown reason). Try /!remote off
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More information is useful; we will try to get past the language barrier
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