I have a 2016 Dyna Street Bob, which has not been ridden for a month or so now due to TX heat.
I didn't have it on battery tender for 3 weeks or so and then I added it.
However my bike doesn't start now.
I did some search and it looks like keyfob is the most common cause, so I ended up replacing the batteries on my keyfob....that didn't fix it.

What are some common causes? Any tips on troubleshooting/resolution?

Attaching a video of what it sounds like when I try to start.

 

The heat may have killed your battery, so get it load tested. That's the most common cause. After that, it's loose or dirty battery cables, especially the ground to frame. You should also check for codes.
I can't play the video, it wants to use some app I don't have or want.

 

Definitely a bum battery.

Just go ahead and replace it, no sense in trying to charge it up and limp along only to get stuck somewhere.

 

The 2026 Dynas are out early!