Message type: E = Error
Message class:  SXMSF -  
Message number: 028
Message text: Message &1 placed in queue &2
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 SXMSF028 indicates that a message has been placed in a queue, specifically in the context of the SAP Exchange Infrastructure (XI) or SAP Process Integration (PI). This message typically signifies that there is an issue with message processing, and the message has been queued for later processing.
Cause: The error can occur due to several reasons, including but not limited to: System
Configuration Issues: Incorrect configuration of the integration scenario or communication channels. Message Format Issues: The message being sent may not conform to the expected format or schema. Connectivity Problems: Issues with network connectivity between systems involved in the message exchange. Resource Limitations: Insufficient resources (e.g., memory, processing power) on the server handling the message. Error in the Receiver System: The target system may be down or unable to process the message for some reason.
Solution: To resolve the SXMSF028 error, you can take the following steps: Check the Queue: Use transaction code SXMB_MONI or
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
SXMSF027 Queue(s) &1 stopped
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
SXMSF026 Start queue(s) &1
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
SXMSF029 Start of message processing
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
SXMSF030 End of message processing
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.