Message type: E = Error
Message class:  RU - Messages for order completion confirmation 
Message number: 154
Message text: Internal number assignment for object (last number was assigned)
In the number assignment for the object &V1& the last number in the
number range interval was assigned.
Proceed as follows:
Branch to number range maintenance.
Enter &V1& as a number range object.
Add a new interval or extend the existing interval.
<DS:TRAN.SNRO>Execute function</>
Error message extract from SAP system. Copyright SAP SE.
The SAP error message RU154 indicates that the internal number assignment for a specific object has reached its limit, meaning that the last number in the sequence has been assigned and no more numbers are available for new entries. This typically occurs in scenarios where number ranges are used, such as for document numbers, order numbers, or other object identifiers.
Cause: Exhausted Number Range: The number range defined for the specific object has been completely utilized. This can happen if the number range is too small for the volume of transactions being processed.
Configuration Issues: The number range may not be properly configured to allow for sufficient numbers, or it may not have been extended to accommodate future needs. Incorrect Object Type: The error may also arise if the system is trying to assign a number to an object type that is not correctly set up in the number range configuration.
Solution: Extend the Number Range: Go
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
RU153 Internal number assignment for object & (numbers are in critical area)
What causes this issue?  In the number assignment for the object &V1& almost all the numbers in the number range interval have been assigned.H...
RU152 Error when assigning number for object &
What causes this issue?  An error has occurred in the number assignment for object &V1&.How to fix this error?  Proceed as follows: Branch to ...
RU155 Confirmations were created at header level for order &
What causes this issue?  You can create confirmations for the order header for the operation A <ZH>combinattion</> of these two types of c...
RU156 Confirmations have been entered at operation level for order &
 You can create confirmations for the order header for the operation A <ZH>combination</> of these two types of confirmation <ZH>wit...
Click on this link to search all SAP messages.