Per the Dynamics GP Email Troubleshooting guide (docs.microsoft.com/.../email-troubleshooting-guide)
--Before Microsoft Dynamics GP's October 2020 (18.3 and later) release, Dynamics GP required that both TLS 1.0 and Basic Authentication (no Modern Authentication) be enabled for Exchange and Workflow emailing in Dynamics GP.
After Microsoft Dynamics GP's October 2020 (18.3 and later) release, Dynamics GP has added the functionality to use both TLS 1.2 and/or Multi-Factor Authentication (MFA). You do not actually need MFA turned on for your account to use the MFA window in Microsoft Dynamics GP, but it does use Modern Authentication vs Basic Authentication.
If you are still on an older version of Microsoft Dynamics GP, you must enable TLS on your local Exchange server. For more information, see TLS completely disabled in 2022.
When Basic Authentication is deprecated (October 1, 2022) you will need to be on a version of Dynamics GP where you can use Modern Authentication (18.3 or later).
--Specific to 'Login Failed: check your login information and try again' messages when attempting to authenticate via the Exchange Log On window in Dynamics GP in order to email and not using the new modern authentication available in GP 18.3:
Cause: There are a multitude of possible causes for this issue. The most common issues are an Autodiscover issue, an issue with MFA (Multifactor Authentication), or Basic Authentication being disabled.
Solution The following path is the best route for generic login issues:
>>Confirm MFA is disabled
If it is enabled, attempt to use an App Password instead of the account’s normal password. For more information, see App Passwords
>>Confirm that Basic Authentication is enabled
Most Exchange Administrators can answer this for you, although the this blog post outlines other routes to confirm the status of Basic Authentication
>>Confirm that Autodiscover is working
You can do this by removing the user from the SY04920 table (Dynamics/System database) and attempting to login again. If this table does not repopulate, then there are Autodiscover issues in the system (or the user doesn’t work). For insights into how this all works, along with other tests, see this blog post
**Note: With Login Failed type of error messages, we have seen some cases where TLS 1.0 was disabled, due to the looming end date and vulnerabilities. If you are still on an older version of Microsoft Dynamics GP, you must enable TLS on your local Exchange server. For more information, see TLS completely disabled in 2022.
As you may or may not be aware, there has been talk of completely removing basic authentication from O365/Exchange Online for the last couple of years. It was supposed to already have been done but got pushed back due to covid and such.
Currently, Exchange Online/O365 have put a deadline that as of October 2022, basic authentication will be permanently disabled moving forward.
Why this is important to us, is that our Exchange emailing in Dynamics GP 18.3 and prior, requires basic authentication to be enabled on Exchange, in order to authenticate.
This being said, since February 2022, we've become aware that Exchange has been disabling basic authentication on some O365 tenants to the point of 50% to 90% failure rate. Some of this is mentioned in these two articles:
techcommunity.microsoft.com/.../2772210
techcommunity.microsoft.com/.../2599824
Exchange Online is making these changes not on the policy level but behind the scenes, this is why it is possible to run a diagnostic against your Exchange Online and have it show basic authentication is still enabled, when it actually is not behind the scenes. This makes verifying basic authentication near impossible for us right now.
These articles above mention a work-around that you can potentially look into, that allows you to use a legacy endpoint to connect to Exchange Online, which still uses basic authentication, which will be valid until October 2022 when basic authentication is removed permanently from Exchange Online.
***NOTE: This often requires you to contact Exchange Online to verify they have enabled the legacy/basic authentication on your O365/Exchange Online email tenants, otherwise this work-around will not work as the 'Exchange Log On' window will never authenticate, always giving a 'Login Failed' message.
Once you have the legacy/basic authentication enabled in O365/Exchange Online, the second part of this work-around to be able to email via Exchange in Dynamics GP, as mentioned in the blog below, is to modify the Dynamics.exe.config file that exists in each Microsoft Dynamics GP install directory and can be used until you're able to upgrade to GP 18.3 or later if not already and begin to use our new 'modern authentication' functionality.
community.dynamics.com/.../emails-intermittent-failing-when-sending-out-of-dynamics-gp-not-workflow-emails
***Again, this work-around is only valid until October 2022, then you must be using the new modern authentication mentioned below or move from Exchange to MAPI emailing in Dynamics GP. ***
All of this being said, the recommendation is to get upgraded to Dynamics GP 18.4 and begin using our new 'modern authentication' feature we added to Dynamics GP. This uses modern authentication and also allows users to have MFA enabled on their user accounts, whereas MFA was not supported when emailing per Exchange in prior versions of Dynamics GP. This is mentioned in these two blogs:
docs.microsoft.com/.../multi-factor-authentication
community.dynamics.com/.../microsoft-dynamics-gp-fall-2020---multi-factor-authentication
By Oct 2022, you must be on GP 18.3.1173 or later, using this modern authentication, in order to email per Exchange, otherwise MAPI would be the only other option, which requires a 32-bit email application.
Please let me know if you have any questions on anything I mentioned here.
Thank you,