Undelivered Mail Returned to Sender

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The mail system
<lainee1019@yahoo.com>: host mta7.am0.yahoodns.net[67.195.228.111] said: 421 4.7.0 [TSS04] Messages from 128.65.197.100 temporarily deferred due to unexpected volume or user complaints – 4.16.55.1; see postmaster.yahooinc.com/error-codes (in reply to MAIL FROM command)