Hi @Tevon2.0 ,
According to the Warning, it may be that you have not configured incoming email for SharePoint server 2019.
Please refer to:
https://learn.microsoft.com/en-us/sharepoint/administration/incoming-email-configuration
This article describes how to configure incoming email for SharePoint Server. This article also describes how to install and configure the SharePoint Migration Tool service to enable incoming email.
When incoming email is enabled, SharePoint sites can receive and store email messages and attachments in lists and libraries. This article describes two scenarios, one basic and one advanced. The basic scenario applies to a single-server farm environment and is recommended if you want to use default settings. The advanced scenario applies to a single-server farm or a multiple-server farm and contains several advanced options from which to choose.
But I find that the Lazy Approval is related to NINTEX, it is a third-party tool. And I find this article:
So, If you still have problem on this, I suggest you go to the Nintex forum to make a request.
Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.
Thanks for your support and understanding!
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