Set people picker at web application level

#Get WebApplication name where you want to fix this issue
$webApp = Get-SPWebApplication http://server:port


# we need to repeat the following block for all the domains you want People Picker to work for on this particular web app
# ——————————————————————————————————————————
$domainInfo = new-object Microsoft.SharePoint.Administration.SPPeoplePickerSearchActiveDirectoryDomain
$domainInfo.DomainName ='domain.net';  # specify the fqdn
$domainInfo.ShortDomainName ='domain'; # specify the netbios name

# =====================================
# This section is only required if there is a one-way trust to the domain and the application pool account does not have access

# First you have to run setapppassword on every server in the farm.
# This sets the encryption key used with the password you enter for the account you specify for $newdomain.loginname
stsadm -o setapppassword -password "Password"
# Where <password> is any string you want to use as an encryption key.
# This needs to be run on every server using the same value for <password>

$domainInfo.loginname = 'domain\sp_farm' # Specify an account that has access to the remote domain
# Do not change anything in the next two lines, it will prompt you to enter the password.
[System.Security.SecureString]$secureStringValue = Read-Host “Enter the account password: ” -AsSecureString
$domainInfo.setpassword($secureStringValue)
# =====================================

$webApp.PeoplePickerSettings.SearchActiveDirectoryDomains.Add($domainInfo)
# Repeat end
# ——————————————————————————————————————————-
# Finally save settings for the web app
$webApp.update()