Dear Christina Copperthwaite,
Greetings! Thank you for posting in Microsoft Community.
As per your description, when you open one of your whiteboards, it gets stuck on the loading page. After you create a new whiteboard, it won't load if you close it and reopen it.
We'd like to help you. Please don't worry, we can work together and try to narrow down the situation.
It seems like you are using Whiteboard desktop application.
If our understanding of the scenario is right, we suggest you go to Whiteboard on the web, open a whiteboard and check the result. It helps you check whether the issue only appears in Whiteboard desktop application.
And you may try to Repair Whiteboard application with steps below:
Close Whiteboard application. Open Windows Settings > Apps > find "Microsoft Whiteboard", click Advanced Options> then click Repair. After that, reopen Whiteboard and check the result.
We appreciate your understanding that sometimes the initial reply may not resolve the situation very soon. However, we can work together to narrow down and resolve the situation. Please kindly provide the requested information to let us work further.
1.Which account do you sign in Whiteboard? Microsoft 365 work or school account, or personal Microsoft Account?
2.Did the issue happen in previous? If not, when did the issue start to appear?
Thanks for your cooperation! I hope you keep safe and healthy always.
Sincerely,
Tina | Microsoft Community Moderator