Why can gmail and outlook send each other, but not with QQ Mail? Is there anything particular about it?

Why can gmail and outlook send each other, but not with QQ Mail? Is there anything particular about it?

Mar.01,2021

was put in the dustbin by QQ Mail

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1bf058e-31cf9.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1bf058e-31cf9.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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