550 5.7.1 We do not relay, account limits apply
Check the account limits for the particular user account, its domain and on the server level.
SMTP sender must be authenticated. SMTP authenticated user must be same as email sender address.
Number of messages: 1000 / day
Maximum message size: 100 MB / message
Maximum recipients: 100 / message
Denied for relaying too often: 50 / hour
Number of connections: 60 / minute
Maximum unknown delivery count: 5 / hour
Blocking time: 30 minutes
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