Message type: E = Error
Message class:  PPC1DM - PP Backflush: Database Management and Communication 
Message number: 307
Message text: The cost center/activity type/CO area must be filled
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 PPC1DM307 indicates that a required field related to cost center, activity type, or controlling area (CO area) is not filled in the system. This error typically occurs in the context of controlling (CO) and production planning (PP) modules when trying to post or process data that requires these fields to be populated.
Cause: Missing Data: The cost center, activity type, or CO area fields are not filled in the transaction or document you are trying to process.
Configuration Issues: There may be issues with the configuration of the controlling area or the cost center/activity type settings in the system. Data Entry Errors: Users may have overlooked entering the necessary information in the required fields.
Solution: Check Required Fields: Ensure that the cost center, activity type, and CO area fields are filled in the relevant transaction. You can do this by reviewing the input screen or document where the error occurred. Validate Master Data:
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
PPC1DM306 User-specific display variant &1 loaded
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
PPC1DM305 SAP display variant &1 loaded
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
PPC1DM308 The display variant &1 entered is being loaded
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
PPC1DM320 Communication error during RFC in the target system &1
What causes this issue?  You want to compare data from the ERP System with data from the APO. To do this, the system must read data form the APO Syste...
Click on this link to search all SAP messages.