Office365 Email - Issue sending emails to icloud.com accounts

[MYK-IT]

Some of our staff are experiencing issues sending, or replying to icloud[dot[com email accounts.

 

They can receive (from [dot]icloud.com) OK, but if they reply (or compose a new email) they get an undeliverable email.

 

Delivery has failed to these recipients or groups:

xxxxx xxxxx (xxxxx[dot]icloud.com)

Your message couldn't be delivered. Despite repeated attempts to contact the recipient's email system it didn't respond.

Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin that it appears that their email system isn't accepting connection requests from your email system. Give them the error details shown below. It's likely that the recipient's email admin is the only one who can fix this problem.

For more information and tips to fix this issue see this article: https://go.microsoft.com/fwlink/?LinkId=389361.

 

As the message states, It's likely that the recipient's email admin is the only one who can fix this problem but after checking the message headers I cannot see anything obvious.

 

Any suggestions would be appreciate.

[Steve21]

Any embedded images/links in signatures? Sometimes it can get over sensitive to these and nuke it (Would be worth trying one of these without that turned on)

 

Steve

[mavhc]

Check your spf, dmarc and dkim settings are correct as a first step

[MYK-IT]

Thanks both,

@mavhc our SPF, Dmarc & DKIM are setup OK, as I spent an age last year configuring and testing this.

@Steve21 I will get staff member to send a plain email, with no attachments to see if that will work.

 

Appears that it may only be one, specific icloud[dot]com account - just awaiting feedback

[Steve21]

I know it's slightly OT, but thought it was interesting to find out today that iCloud mail blocks emails being delivered if their icloud is full!

 

Remote Server returned '550 5.4.300 Message expired -> 450 4.2.2 <***@icloud.com>: user is overquota

 

1990s want their errors back! (Never actually knew it counts against a users icloud storage though... Wonder how many of them do?)

 

Steve

[mavhc]

Apple's new business model is selling icloud storage.

[Arthur]

Apple's new business model is selling iCloud storage.

The 2010s want their cloud storage back!

 

 

With a paltry 5GB of free storage it's not surprising Apple users run out of space. That's 3 times less space than Google gave everyone over eight years ago with Drive.