enque/delay_max is a SAP Parameter attribute which is used to control Number of retries if enqueue request is rejected information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
Number of reattempts after a lock request is rejected. This affects the
non-interactive processes (such as background processes). If a lock
request was rejected, the system makes another attempt to set the lock
approximately 1 second later. This is done enque/delay_max times
(default 5). The work process is blocked during this time.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.