Can you Use ‘Let’s Encrypt’ on Hybrid Exchange?
KB ID 0001770 Problem A few months ago I wrote an article about getting free exchange certificates with Lets ‘Encrypt’. And that still works peachy, I implemented it on my test Exchange 2019 server (in Hybrid mode) and all appeared well. Some time later, (remember this is my test network so it’s not in production.) I noticed that mail was not getting forwarded from O365 to the on premises Exchange server. I’ve...
Mail Routing Issue ‘451 5.7.3 Cannot achieve Exchange Server authentication’
KB ID 0000791 Problem While putting in a New Exchange 2010 server today, I test moved a mailbox to this new site, and could not get mail to flow to the Exchange 2010 server at the clients main site. 451 4.4.0 Primary target IP address responded with: “451 5.7.3 Cannot achieve Exchange Server authentication.” Attempted failover to alternate host , but that did not succeed. Either there are no alternative hosts, or delivery...