1. The environment is too distracting or overstimulating at that moment.
Even if you've been there before, or believe it's a scenario your dog should be able to handle, if you’re feeling as though your dog isn't listening to you at that moment in that particular environment, the best thing you can do is encourage your dog to take distance by walking away and doing something less challenging for them, to help you both reconnect.
This will help your dog cool down until you feel that you're able to communicate with one another once more, before trying again.
If most environments seem to have this effect on your dog, it could be a sign that he/she is in need of a more controlled and manageable setting first, and scenarios focused more on you both accomplishing a single or few exercises together (such as agility training, nosework, etc). Both will help your dog feel mentally and physically fulfilled and are also available mostly as group classes.
2. There may be a disconnect in your communication.
If listening to your voice and responding to your every word/cue consistently yields a rewarding and enjoyable outcome for your dog, such as a positive reinforcer (meaning they get something they want like treats, your attention, a toy, etc) then they are much more likely to pay close attention to your communication towards them, under most circumstances.
However if your verbal guidance doesn't always associate itself with your dog's positive emotions that way, then he or she is much more likely to disconnect and disengage from your communication and overall guidance, especially in more distracting scenarios.
To avoid feeling a disconnect, practice saving your voice, your attention, and most of your cues for interactions that not only mean the most to you but also mostly for moments when your dog has done something you're genuinely happy with. This will only serve to increase the value of your voice, praise, and overall attention.
Pay close attention to your daily interactions with your dog, as chances are that there are small things that your dog is doing on a regular basis that you can start focusing your attention, voice, and commands towards, more than ever before in order to reconnect further.
As you work on enhancing your connection and communication, you will then feel more confident tackling environments where you previously felt a disconnect, once again.
3. Your dog is feeling overly tired/overwhelmed/over their threshold.
This can happen anywhere, at any time, and under any circumstance. Our world doesn't make 100% sense to all dogs and it affects them individually. But not only that, dogs are by nature curious and sensitive in ways we may not always fully understand.
However, just like us, dogs can have bad days, or simply feel like they're not in the right mood or mindset right there and then. This can get in the way of even the strongest pet-parent-dog relationships and that's okay.
The first step is realizing that your dog may need a break from that scenario altogether and if walking away is not possible, then you can try providing them with a frozen, stuffed Kong to help them chew on, lick, and self-soothe or a strong but enjoyable smelly treat to help focus their thoughts and feelings a little.
The next step is reviewing what they were doing, for how long, and how they were feeling every moment before you experienced difficulty communicating with one another. That game of fetch might have gone for too long, or been too exciting, or perhaps their food puzzle was too hard, or too engaging to begin with. This is when it may be a great idea to change scenery, walk away, take a break, and do something else for a bit.
In all three instances above, one thing they all have in common is that they will challenge you to lower, adjust and lower your expectations when interacting with your dog if you're having difficulties. If you make it a habit of practicing more habits where you find yourself listening and paying close attention to your dog's feelings and emotions, you will discover the patterns and daily habits that got them to that point, to begin with.
Don’t forget that dogs are both products of their environment and individuals!
No matter the reason, be sure that you have all the right tools with you! One of my personal favourites tools to use to help my dog take space as needed is a hands-free leash! Particularly indoors, where you can safely tie or clip it to your waist, leaving your hands free to focus on exchanging treats for good behaviour and more.