Continued from my above reply.
sccatke Said:
"My iphone 11 pro connecting Wifi and mobile network become very slow[...]Additionly,I can't connect to Appstore anymore and Apple server always failed to me after tying Apple ID password. Please fix this problem if possible."
-------
Troubleshooting a Locked Account:
Locked Out:
For note: You are you locked out of your Apple Account. There is no iCloud account.
So, Contact Apple Support:
Visit this Link: If your Apple ID is Locked or Disabled - Apple Support
Why Accounts Become Locked:
When your iTunes Account has been disabled, and that often happens due to suspicious activity --- Perhaps nothing on your part. They disable it for no more than Security & Privacy concerns.
Possible Reasons Could Include:
- Too many unsuccessful login attempts
- VPN (Virtual Private Network) usage
- Consistent transactions
- Session Times Out
- Disobeying Terms & Conditions
So...
To Re-Enable it:
As you might suspect, no one here would know the reason for this occurrence, of course. So, contact Apple Support. They’ll know why this occurred and will run you right through the fix.
Contact Apple Support:
Note: Phone calls are taking a bit to go through at the moment, due do lots of calls. With the Coronavirus Pandemic, many are at home at the moment, with much time on their hands to contact Apple. So, just stay on the line, and you will get through :)