If you ever need to get a list of distribution list members, it is not ideal to use the 365 Admin panel. Instead, use the following PowerShell script:
Setup:
Install-Module ExchangeOnlineManagement -Scope CurrentUser
Connect-ExchangeOnlineScript:
Get-DistributionGroupMember -Identity "DISTRIBUTION_LIST_NAME" | Select Name, PrimarySmtpAddress | Export-Csv -Path "C:\temp\Members.csv" -NoTypeInformation
You will find the csv in the C:\temp\ directory.
Credit: