Failed to connect to putty – Ask Ubuntu

I typed "sudo bash". The user name has been changed to "root" from the original user name. uncertain of what I should do in "root", then I closed Putty.

After reopening Putty, with the correct "login" password, the tester and the Putty screen indicated "Access denied".

please indicate how I can reconnect. is the connection failure linked to the "sudo bash" command?

Thanks for the advice.