License manager such as Esri license manager which is based on FLEXnet publisher are usually a reliable software. Based on my more than 25 years of using different license management software such as FLEXlm, HASP, IBM LUM and others, it does fail from time to time. In such cases the damage can be significant, lost work hours, delays in project delivery and more.
The following article lists the alerts every GIS leader needs in order to reduce the damage and keep license availability:
What do you think?