This is usually because the text style you previously used is no longer available, or the text data was not saved correctly.
You can follow the steps below to recover your text:
Step 1:
Double-click the relink icon. Your original text content should appear.
Step 2:
Copy the text, then delete the old text box.
Step 3:
Add a new text box from the left panel and paste the copied text into it.
This will allow you to continue editing your text normally.