I don’t think your chakras are blocked just because you don’t seem to see anything in a meditation.
When we “see” things during meditation, it can be hard to see with our mind’s eye because we’re expecting to see actual images. In my experience, these images actually tend to be more hazy and definitely more in my mind, almost like a very fuzzy dream. If I get clear images, it’s usually deeper in meditation or if I’m calling upon my Gods. They tend to make things more clear.
Meditation isn’t about sitting down and clearing your mind or even seeing things during visualization. It’s also possible that you can’t visualize. There’s a sort of…not a condition, but something that people can have called aphantasia. You can read more about it in this post (Witching with Aphantasia - No Mind’s Eye & Can’t Visualize!) but it basically means you don’t have a mind’s eye and can’t “see” images in your mind.
Can I ask what the goal of your meditation is? Is there a specific thing you’re trying to see, or just following a guided meditation? Knowing this can help me give you a more specific answer and even gather some resources that might help you a bit more.
For now, here are some other resources about meditation.
→ Meditation Benefits & How to Meditate – Spells8