I bought a realm tonight to play with my friends, they can get on but I cannot. Everything works until I actually try to open a world. Then it crashes. This is the case for Single Player as well.
When I reduced the version to 1.8.9, Single Player worked perfectly but I couldn't play on a realm because the version was outdated.
I have tried completely uninstalling and reinstalling both Minecraft and Java, as well as making sure my account was migrated.

Attached is a screenshot of my error message.

Thank you for your help.