Thanks for reaching out!
This sounds like it could be the same as the issues we’ve been seeing. When updating to a new major release, there could be some markup changes incompatible with the cached generated styles. We need to make sure that there’s always a way for the style cache to be cleared.
I suggest that you go to X/Pro > Settings > System then click the Clear Style Cache button to clear the style cache manually and also clear any 3rd party plugin cache you have installed or integrated to your website.
Only if none of that helps, please give us the following information in a Secure Note.
- WordPress Login URL
- Admin level username and password
You can find the Secure Note button at the bottom of your posts.