I have the most up to date version of 1.8 running. Got this error message and an email blast stalled about 100 into an 800 subscriber list.
Sending error. Check your mail settings.
Server said:
RCPT TO: <stxxxyg_@blahblah.com>
250 2.1.0 ... Sender ok
250 2.1.5 ... Recipient ok
EDIT
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Just had another stop (at 700)
Server said:
RCPT TO: <cccxxxx@xxx.ca>
250 2.1.5 ... Recipient ok
354 Enter mail, end with "." on a line by itself
