Text went non visible in editor

Good morning,
I would like to report this problem I faced. I have edited a page and added many lines of text. Everything was visible in the editor and in the published site.
The following day when reopening the editor I found the page "blank". The text is still there, (indeed if I select a line and change color I can see the modification online) but non visible in the editor.
No settings were changed and all the settings of the text seem to me identical to other text in the website which is clearly visible.
Do you have suggestions on why this could have happenen and how to solve?
Thank you

I already replied to a duplicate post of yours, please check it