Odd alarm issue

[Ford freak]

Hello new here but have been hanging out in the background, I have an 08 Limited Expedition with 155000 miles on it we've owned this car for over 10 years and had no real major issues since we've owned it but recently we've had trouble with an intermittent issue with key fob, I, replaced the battery and all good for a while but now the issue has returned with the added bonus of key no longer works at all so I opened the door using the key no alarm trigger but when insert the key into the ignition and start the car the alarm triggers what gives here?
Thank you

 

[Hondobud]

If you have more than one fob you should replace all the fobs batteries, a weak battery in any of your fobs could be your problem. My 2003 alarm would go off whenever it wanted. I figured out it was a worn out passenger door light / door ajar switch. Do you ever see a door ajar light flickering or on? Also spray lube the door latches, rear window catch mechanism and the rear door catch m. also the hood catch m if its connected to the alarm. See also https://www.youtube.com/watch?v=Dxj0n4EQsBU (key fob programming reset) good luck

 

[Ford freak]

Think it was the hood switch and I did go around and check all the locals and tailgate latches like you said.
No problems since.
Thx the info