Boards usually fail to load because your Pinterest connection has expired, Pinterest's API is briefly slow or unavailable, or the connected account is new and doesn't have any boards yet. This is separate from your Pin's content — it just affects the board picker.
Common causes
The Pinterest connection has expired and needs to be renewed.
A temporary issue on Pinterest's side.
The connected Pinterest account has no boards yet.
What you can try
Tap the board field to retry loading boards.
Go to Settings → Pinterest and reconnect if it shows as expired.
If the account is brand new, create a board on Pinterest first, then retry.
Wait a moment and try again — Pinterest's own service can be briefly slow.
If boards still won't load after retrying, contact support.