emails being sent to plus net address are getting returned with 552 error

[#1]

I have become aware that an email that is required has been blocked with the message 552 spam message however these have then been forwarded to the same address and are getting through.

These are cases where the email is wanted and the rejection spotted but how do I get this resolved and what if these emails hadn’t been spotted I could have missed important ones.

is there a way to stop this happening 

is there a way to inform the recipient that they have been blocked 

[#2]

Is the email being sent direct to the Plusnet address or is it being forwarded by a third party.

For example, is the email addressed to you@youraccount.plus.com or to you@somewhere-else-not-hosted-by-plusnet.co.uk which then forwards to you@youraccount.plus.com

Who is the sender?

[#3]

Hi

it is being sent to you@youraccount.plus.com

the sender is sending this email to several people and when they have spotted that this has been rejected has then forwarded it to you@youraccount.plus.com and the forwarded message is received 

[#4]

There is anecdotal evidence that bulk mailing where the addressees are BCC'd and there is no TO addressee heightens the SPAM assessment of emails.

Can you ask your correspondent how they are sending their bulk email - do they specify at least one TO addressee?  Many such mailers send TO no-reply@their-domain.com (as well as the the BCC'd)to reduce the risk of an enhanced SPAM assessment.