Popup message "You appear to be offline, your progress may not be saved"

I am logged in and have internet access, but in the top of the screen pop-up appears “You appear to be offline, your progress may not be saved” and because of it I can’t save my progress.
I use the last version of Chrome. I tried to clean cookies, history in browser, tried to visit freecodecamp.org in private/anonimous mode screen, but all of it could not resolve my problem.
Please, help me with this issue.

Happens to me right after logging in, I have found by completely closing the browser I logged in with and then coming back to site it works better.

Unfortunately, it did not help for me. Pop-up “You appear to be offline, your progress may not be saved” appears again. I can’t continue any course.

check if your clock is set to the right time and correct the time