Because another person (or you) is reading The world With this account on another device.
You cannot read The world that on a single device at the same time (computer, telephone or tablet).
How can we not see this message anymore?
By clicking on ” »And making sure you are the only person to consult The world with this account.
What will happen if you continue to read here?
This message will appear on the other device. The latter will remain connected with this account.
Are there other limits?
No. You can connect with your account on as many devices as you wish, but using them at different times.
Do you know who is the other person?
We advise you to Modify your password.
Source: Lemonde