Diagnosis
The system tried to lock a material (used by you) for the availabilitycheck. An error has occurred in SAP lock management: Either therehas been a communication problem with the enqueue server, or there hasbeen an internal system error, or the SAP lock table has overflowed.The lock attempt was therefore not successful.

System Response
To avoid delaying your work any longer, the system has ended the lockattempt and has not, therefore, been able to perform the availabilitycheck for this item.

Procedure
The system could not determine any confirmed quantities for theitem you processed (new). For that reason, you should perform anew availability check for it.
You should also be aware that the failed lock attemptcan also have an effect on theavailability check of other items or on other usersup until the saving of the document,because too much or too little is reserved.