After updating to 1.14, a bug prevents users from accessing Realms servers in their list due to an issue with the banner above the list that advertises buying a Realm. Users who have already purchased a Realm are not affected as the banner does not appear.

Note: I only have access to a single Realm so I cannot test it with anything past the first one in the list, however @LudwigElric118 has reported that their friends are experiencing the same problem with multiple Realms

Steps to reproduce:

From the main menu, upon clicking "Minecraft Realms" to access the realms select menu, the green "Want to get your own realm? Click here for more info!" banner that usually appears is instead obscured by the first Realms server in the list. Clicking it only opens the "Buy a Realm!" popup window as if the banner were still there, so the server can never be joined.

Resizing the game window in any way pushes the Realms list down into its correct position to reveal the banner, but does not update the clickable areas of the screen. Clicking the server now does nothing, and clicking the banner still opens the popup window. The only way to access the Realm is to do the following:

1. From the main menu, click "Minecraft Realms"
2. When you can see the Realms selection screen without the green banner, resize the window in any way to make the banner appear (must not be playing in fullscreen mode)
3. Click the green banner
4. Close the "Buy a Realm!" popup by clicking outside of it, NOT by clicking its 'X' button
5. Click the now activated "Play" button WITHOUT clicking on your Realm again

The attached video is a demonstration of the process