Hyundai Azera won't start

Reprogram your car fob key again to accept the remote. If reprogramming doesn't work maybe your fob key button are the problem.

Why is my 2007 Hyundai grandeur key not starting my car

You will likely need either a new transponder key or the module that reads the transponder to activate the immobilizer (the security feature that is preventing your car from starting) has some issue. It can often be the case that in somewhat older cars connectors can become loose or dirty/oxidized, this is especially likely when it is an intermittent problem. Unfortunately, a dealer tech will often replace these expensive modules without first trying to just separate the individual connectors that could potentially be causing the faulty connection to clean/inspect then reseat the connector pins (male and female sides both), which in a great many cases for a plethora of electronic faults in all makes and models of cars is often enough to fix intermittant electronic issues - or actually just do the latter and charge for the former. After all, why offer a free fix when they can charge for six hours shop time and a 200% markup on parts? So either find a reliable, trustworthy independant mechanic, or get a repair manual and learn to read a wiring diagram and do it yourself. This is easier than it sounds, doesn't take much time, and there are a great deal of resources to help - you can do it if you want to, no matter how non-technical you may have been convinced that you are. Haynes manuals, if one is available for your model, are awesome for newcomers to DIY vehicle repair, as they are written with an average car owner (NOT an average car mechanic) in mind, and their staff literally write each manual by buying one of the featured model of vehicle and dis-assembling it, then putting it back together, taking plenty of pictures of the process then writing up each section of the process relevant to specific tasks associated with individual repairs as they experienced it - versus factory manuals, which are written by technical writers based on notes from engineers referenced to engineering diagrams, and thus entirely (and intentionally) devoid of any practical non-technical information. The other potential problems could be faulty power connections to the same modules (especially grounds, which are often located remotely somewhere along the wire harness and not necessarily anywhere near or apparently related to the module in question) OR a failing solder connection or electronic component inside the module itself, which for all but the most skilled DIYer I would suggest replacing the module in that case. Keep in mind if replacing any security-related modules that one will need to have access to a dealer-level diagnostic/programming interface in order to code the module for your car specifically, or depending on the model just having the key transponder (the chip in the top plastic part of your key that disarms the immobilizer) from the donor car if replacing with a used module might suffice. If this is the case most often used parts sellers that are knowledgeable enough will sell the two together as a package (check ebay/forums/etc.) I hope that helped, good luck!