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DMARC - Procedure to follow
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Due to recent changes to email handling by Google and Yahoo for anyone sending more than 5,000 emails daily, you should ensure that you have a DMARC record in
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your DNS settings.
If you don't know anything about DMARC, then we recommend you add the following DNS record:
- _dmarc.mosamuseum.com. IN TXT "v=DMARC1; p=none"
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Please check afterwards with
https://mxtoolbox.com/dmarc.aspx: it shouldn't include any errors (i.e. anything flagged with 
). Please also read https://support.google.com/a/answer/10032473 to progressively improve your DMARC record.