no start

Hi everyone,I have a 2018 Hyundai sonata SEL with 45k miles under and its under warranty. On starting it in june after a whole day at work it slow started like a key start would. Took it to the dealer and they said it didn't have any codes and therefore they cant fix something that isn't broken. However they said they tightened the push start button. It appeared to be fine after that until Aug 14 when it did the same thing again except rather than slow start it didn't start at all just all light on the display came up. After many attempts I decided to try the remote start which was dealer added on purchase and it started.So I made an appointment for the following week to have it checked. That evening I decided to check the battery with my multimeter and it showed under load with lights on 11.4 volts and the headlights went out completely and came on after a few seconds. Jump started the car and it started right away went to autozone got a battery all was well until wednesday same thing again, it won't push start lights came on and a click. I remote start it the next day because it still won't push start and it took me 4 tries with that to start. Took it to the dealers again they had it for 2 days and at no point did it refuse to start, they told me there are no codes showing an issue and they can't fix it unless its not working.I just don't get that I asked them to fault check the starter ignition switch etc because I had the battery replaced so it can't be that. They told me it refused to do what I told them and to pick it up so I left it there.The funny thing was I recorded the instances it didn't work and showed them the video. Decided to turn to youtube and saw some similar issues being repaired. I would like some help or pointers with this issue. Thanks Sorry a pic is all I can upload the video was too big

Its an automatic, what you mean "push start it".
I really don't have the tools to check much only a multimeter.
I am going to the dealership shortly to pick it up and hopefully be able to check any ideas that may come up in this forum. Thanks

Yes just rewatched the video and there is a click

Does anyone have any ideas what to do?
Scannerdanner do you have any ideas? or can you fix my issue?
Thanks

Start by checking connections at starter make sure they are tight as a loose connection can cause this intermitant issue. If you find one loose make sure to clean the contact points with a wire brush and disconnect the battery before cleaning.
Check ground wires for loose conections on engine block and battery ground wire from engine to battery if there tight. Also look for green crusty buildup on wire ends.
With mutlimeter set to ohms while battery disconnected check neg batt cable from engine block to battery for resistance. It should read 0 ohms.
Repeat process with positive battery cable as well that goes down to starter. Should also read 0 ohms.

Once you have checked all powers and grounds for starter for loose connections. then with a helper (((Being mindful of moving parts of engine))) put your multimeter on dc volts red lead to signal wire and black lead to clean metal part of engine and check the starter solinoid for start signal when helper turns key to crank position. You should see battery voltage and starter should crank. If you see voltage signal and starter does not crank this could be solinoid malfunctioning. If you don't see a voltage your problem is going to be in wiring towards the ignition. This could be in one if the following
starter relay
the park neutral switch
the push to start switch

the batteries in your car key/remote start fob (possibly both) if you have not changed batterys in them yet. Which you can remove the batteries and test them with your multimeter and compare voltage to what is on battery. Replace them if they are low or dead. This can cause the same issue of randomly working and not working to start car. Let us know when you have done these steps and qhat you find out.

Thanks will do

Cleaned and tightened all the grounds from the harness in the engine and from the battery some were loose and rusted after checking starter it turned out not to be working.I had it towed to the dealer and they ordered and changed it and i'm back up and running. I will keep you guys posted if I have repeated issues. Thanks