When bluetooth pairing most devices have blue or white leds flashing. Red is most used as a problem indicator.
I suggest you try a reset of the headphones following the Beats by Dre instructions.
'''Reset'''
Make sure your headphones are not plugged in to your USB charging cable.
# Press and hold the power button for 10 seconds.
# Release the button.
# The battery Fuel Gauge LEDs will all blink white, then the first will blink red—this sequence will happen three times.
# When the lights stop flashing, the reset is complete.
[https://www.beatsbydre.com/hk/support/how-to/reset-solo2-wireless#:~:text=Press%20and%20hold%20the%20power,flashing%2C%20the%20reset%20is%20complete.|Source]
After that try to pair again:
'''Pair your headphones'''
To pair your headphones with your device, follow these steps:
# If you were using the RemoteTalk cable, unplug it.
# Turn on your headphones. Hold the "b" button down for 2 seconds to put your headphones into pairing mode. The LED indicator light will pulse white.
# To connect your headphones to your device, select Solo2 Wireless on your device. If you’ve used Beats Updater to rename your headphones, that name will display in the list.
Your headphones reconnect automatically to the last device that you used with them.
[https://support.apple.com/en-au/HT205670#pair|Source]