Welcome Laura Santoro,
Thanks for reaching out to Microsoft Q&A Forum. I understand you purchased Minecraft: Java Edition using a new Microsoft account but attempting to start the Realms 30-day free trial redirects you to Minecraft.net and displays the “Oops, something went wrong” message.
Could you confirm whether you are signed in to Minecraft.net with the exact same Microsoft account that owns Minecraft: Java Edition? Also, have you ever activated a Realms trial or subscription using this Microsoft account before?
In the meantime, you can try these steps:
1, Clear the browser data for Minecraft.net
- Clear cookies and cached website data associated with Minecraft.net
- Close and reopen the browser
- Sign back in and try again.raft.net using the Microsoft account that owns Minecraft: Java Edition
- Try the Realms subscription page again
2, Try starting the subscription through another supported browser or an InPrivate/Incognito window
- This can help determine whether existing browser session data is interfering with the subscription page
3, Make sure the correct Microsoft account is being used for the subscription
- Minecraft: Java Edition Realms subscriptions are associated with your Microsoft account
- If multiple Microsoft accounts are signed in within the browser, sign out of the others temporarily and try again
Looking forward to your update.