Hi Cyndi,
it indicates that the receiving email system rejected the message
because it is thinking that this groups.io server is sending spam,
what is not true.
So contact this member and tell him to use a different email
provider.
There are other options, but they all make no fun at all:-)
Regards,
Isidro
Am 19.11.2019 um 00:38 schrieb Cyndi
Law:
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Failed - 550 5.7.1 [C15] RBL restriction: Blacklisted by Internal
Reputation Service - 66.175.222.12
