Email blacklist - *.prod.exchangelabs.com

Good morning, An incoming mail from the Microsoft 365 environment (which of course hosts thousands of customers) was blocked because of IP blacklist; Error: 550 5.7.350 Remote server...
Client host is blacklisted - Appears to be false positive

Hi. Recently, we are unable to send emails to any users using Sophos system. Keep on receiving bounced emails. We tried going to the sophos link to request delisting, it however show that the IP address...