Postmaster problem

[#1]

My default mail address (appearing on outgoing mail) has for many years been postmaster@mydomain.plus.com, with no problems until recently.  Actually it's a catch-all address, and anything@mydomain.plus.com should get through.

It now appears that some commercial/business mail servers are blocking postmaster@....plus.com, resulting in mail being undelivered.  My bank has written to me, asking me to update or confirm my email address, due to repeated delivery failures.  When challenged, they could not offer any explanation.  It has started to happen with other organisations too.  It's quite a serious problem, because you don't know what mail hasn't been delivered.

Having changed my address to somethingelse@....plus.com, e-mails from these organisations are now being delivered once more.

Does this make sense?  Are some mail servers treating 'postmaster' as a suspicious or non-genuine address?  I've searched the forum but not found a similar report.  Perhaps I'm the only customer to use 'postmaster' rather than substitute my name?

[#2]

Since postmaster will normally exist with all email domains it could be an attractive choice for spammers when they forge an address. It looks important too.

Most organisations would want more than a plain-text email when a transaction is being negotiated. However perhaps decisions have been taken to encourage clients to change their practices to make it a little easier to detect fraudulent messages.

[#3]

Thanks for your reply.  I agree that a postmaster@ address does look kind of suspicious, but I originally kept it as my routine address for reasons of anonymity and/or couldn't be bothered to change it.  It has only recently started to cause problems, i.e. undelivered mail from some businesses. 

I posted this because it doesn't seem to be well-known.  Perhaps PlusNet should be warning customers not to use postmaster@ but rather change it to something else.  That would be my advice too.