iCloud server blocking email from legitimate senders

This is not a junk mail or spam filtering issue on the client side.

Other iCloud users have previously raised this issue, and iCloud has not offered a solution.

Over the past few weeks, several legitimate emails have been blocked from my iCloud account. These emails were not delivered as junk but were blocked from reaching my inbox.

The blocked emails I am aware of were sent from known contacts that were previously received by my iCloud account.

Here is the message that senders receive from iCloud when their email to me is blocked:

Your message to [my iCloud email address] has been blocked. See technical details below for more information.

Please allow all emails to reach my inbox again. These are critical emails related to my work.