This is AMD explanation and troubleshooting steps for Error 186: https://www.amd.com/en/support/kb/faq/gpu-kb186
I suggest you download the latest RX 590 AMD Driver and save it from here: https://www.amd.com/en/support/graphics/radeon-500-series/radeon-rx-500-series/radeon-rx-590
download free program called DDU (Display Driver Uninstaller) and run it in Safe Mode with the internet disconnected. Once it finishes removing all traces of the AMD Driver on your computer and boots back to Windows Desktop with the internet still disconnected. Go to the Root Directory and check to see if you have a folder called C:\AMD. If the AMD Installation folder was generated delete the entire folder BEFORE installing the new AMD Driver package. This will prevent your current AMD installation from being corrupted while being installed and with the Internet disconnected prevents Windows Update from downloading and installing a different AMD driver before you have a chance to install the new driver.
Now run the AMD Driver package you downloaded. Once it installs correctly then you can now reconnect to the internet and again delete the newly created C:\AMD folder in the Root Directory.
You shouldn't be getting any more AMD installation error 186 since you did a clean AMD driver installation.