NTLM is available for Exchange on-prem customers.
NTLM authentication protocol is supported only for Lightning Sync customers working from Exchange 2016 or 2013 servers and connecting to Salesforce using a service account.
Please see our Connect Microsoft Exchange with Salesforce Using NTLM Authentication Protocol document for more information
This change applies to Lightning Experience, Salesforce Classic, and all versions of the Salesforce app in Professional, Enterprise, Performance, Unlimited, and Developer editions.
Let your IT professional know that NTLM is now supported for certain servers. If your company prefers to connect to Salesforce using NTLM, have your IT professional enable NTLM and disable basic on your Exchange server.
If both basic and NTLM are enabled, Lightning Sync gives connection preference to basic.
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