Start with Step 6 and reverse the settings back to the default:
Essentially:
Run commands in order:
Get-OwaVirtualDirectory -Server <server> | Set-OwaVirtualDirectory -BasicAuthentication $true -AdfsAuthentication $false -FormsAuthentication $true
Get-EcpVirtualDirectory -Server <server> | Set-EcpVirtualDirectory -AdfsAuthentication $false -BasicAuthentication $true -FormsAuthentication $true
followed by IISRESET