If you have somewhat capable Android phone with Android 10(common traits of the devices facing this issue), you might have faced this error. It looks something like this

Amazon Prime Video Playback Renderer Error

So what do you do? Your first instinct would be to google Playback Renderer Error and look for solutions. Most people would do the same instead of contacting customer service(link to which is provided in the error message itself). Why? Because chances of getting a customer service representative who can actually solve your issue without wasting your time is pretty low.
So, you googled Prime Video Playback Renderer Error and followed some links in the search results. What are the solution? Let me guess, most of them tell you these three solutions
  1. Clear cache & data and then try again
  2. Uninstall the app, restart and then install again
  3. Try different version of the app
If you have some experience in troubleshooting Android apps, then you might already have tried them all. Now you're frustrated that everyone is repeatedly telling you what you already know(and did). Now what do you do? Ask on Facebook? Discussion forums?
Chances are, you'll get the same answers over and over again. So without wasting your time, let me tell you how you can fix this simple error.


How to really fix Amazon Prime Video Playback Renderer Error

If you are still here then most probably it's not a matter of compatibility issue of Android 10 and Amazon Prime Video. It's just the default settings of your Android device. 
To fix this, go to settings of your Prime Video app tapping on 'My stuff' icon on lower right. Then you'll see the settings(gear) icon on top right.
Amazon Prime Video Playback Renderer Error

Then you'll see various options, the very first option should be Stream & Download, tap on it.
Amazon Prime Video Playback Renderer Error

Then at the last option there should be Use hardware acceleration. Disable it and you'll be able to watch your movies and TV shows now.
Amazon Prime Video Playback Renderer Error
If you or someone you know was facing that PLAYBACK_RENDERER_ERROR and this post helped you then check out the some of my other posts and share my blog with your friends. Enjoy your Amazon Prime Video.

Update

Sorry for not replying to the comments earlier. I was focusing on other stuffs. Some people are complaining that after following these steps, they're not able to stream in HD/4K. My method disables the higher quality streaming.
So I did some research to find out the root of the issue. Turns out, not only you need DRM certification(Widevine) but your device must be acknowledged by the streaming service also. Here are the list of verified devices for HD streaming, check if yours is present or not
  • Samsung phones – All Samsung M-series and A-series phones launched in 2019 support HD Streaming (except for Galaxy M10). Galaxy A7 (2018), Galaxy A9 (2018) from last year support HD streaming as well.
  • Realme Phones – Realme XT, Realme X, Realme X2, Realme X2 Pro, Realme 5 Pro, Realme 5s (Realme 6 Pro and Realme 6 (fixed in May 2021) have L1, but HD streaming is currently not supported)
  • Xiaomi Phones – Redmi K20 Pro, Redmi K20, Poco F1 (Redmi Note 9 Pro and Note 9 Pro Max have DRM L1, but do not support HD streaming on Netflix and Prime videos)
  • OnePlus phones – All OnePlus phones launched in 2018 and 2019 have HD Streaming support
  • Vivo Phones – Vivo Z1x, Vivo V17 Pro, Vivo U20, Vivo S1 Pro
  • Asus Phones – Asus 6Z, Asus ROG Phone 2
  • Lenovo Phones – Motorola One Power
  • Huawei Phones – Honor View 20, Honor 20
  • LG Phones – LG V30, LG G7 ThinQ (not on Amazon Prime), LG V40
  • Nokia Phones – Nokia 6.1 Plus, Nokia 7.1, Nokia 8.1 Plus

 
Note: This list might not be upto date when you're reading. 

Note 2: My Realme 6 now supports HD streaming, ie no need to disable hardware acceleration. I'm not sure exactly when it was fixed but I received a patch for my phone and app was also updated this month. I'm yet to verify with other problematic devices. I will update once I verify with others.