Everything went normal during study of Online Book . Then sudden I tried to enter Online Book during Notebook session and get IP problem. All other connection are performed as normal. I have access of all my files in the Wolfram Cloud. I cleaned cookies, ipconfig /renew, restart....
Functionality is restored. Thanks
Thanks for reporting this! It seems to be an inconsistency in the server configuration after the recent Cloud 1.55 release. The "online book" (Elementary Introduction to the Wolfram Language) and the documentation center are pointing to the wrong URLs. We're working on a fix.
In the meanwhile, you can reach the book directly here: https://www.wolfram.com/language/elementary-introduction/2nd-ed/ and the Documentation Center is available here: https://reference.wolfram.com/language/
Sorry for the inconvenience.
This is fixed now.
