iPhone 4s iphone can't connect to iCloud for backup, nor perform software update
Trying to backup my iPhone 4s version 8.4.1 (12H321) to iCloud but it won't connect to iCloud. When I sign into my account on my iPhone 4s, I get the notification on my other devices of a new device accessing my account. When I click "allow" & even get and use the security code I am still unable to access iCloud. I am able to try multiple times without locking my account. I am certain I am using the correct password. I am able to use iMessage, for example.
I just cannot turn on backups, nor can I perform a software update to iOS 9.3.6. When I click "Download and Install" option, it almost immediately goes blue again indicating I can/need to click on it again. I have 19.2 GB available, and the update is only 856 MB.
Has anyone seen this or can suggest a fix? Thanks in advance
Earlier iPhone models