Message type: E = Error
Message class:  /AIF/LFA_MES -  
Message number: 146
Message text: Enter download type for Excel
Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.
To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.
Unfortunately, there isn't any extra information in this error notice.
First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).
Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.
You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.
The SAP error message /AIF/LFA_MES146 Enter download type for Excel typically occurs in the context of the Application Interface Framework (AIF) when trying to download data to Excel. This error indicates that the system requires a specific download type to be specified before proceeding with the download.
Cause: The error is usually caused by one of the following reasons: Missing Download Type: The user has not specified a download type in the interface or configuration settings.
Configuration Issues: There may be issues with the configuration of the AIF or the specific interface being used. User Input Error: The user may have overlooked entering the required information in the download settings.
Solution: To resolve this error, you can follow these steps: Specify Download Type: Ensure that you have selected or entered a valid download type in the relevant field before attempting to download the data to Excel. Check the interface configuration to see if there are predefined download types that you
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
/AIF/LFA_MES145 Invalid file adapter configuration &1/&2/&3 provided
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
/AIF/LFA_MES144 No file data to be saved
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
/AIF/LFA_MES147 No input file could be determined
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
/AIF/LFA_MES148 No output file could be determined
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
Click on this link to search all SAP messages.