Hello, friend!
First question
To change the password of the root(web) user, perform the following steps:
1. Log in to the web page as a common user or administrator.
2. Choose System Tools > Change Password to change the password of a common user account.
3. Click Apply.
Second question
You can check whether the link quality is codeless on the OLT, whether the Ethernet port between the PC and the ONT is FE or GE, and whether the rate is limited on the OLT.
The WLAN download rate is also affected by material interference and the number of ONT users.
If the fault persists, you can modify the DBA profile and traffic table issued by the OLT to increase the ONT rate.
Thanks!