How to add owner in DL if there is no owner.

For this we need to use the power shell because from GUI it is not possible.

Open Power shell ISE as an administrator

Run below commands:

Set-ExecutionPolicy RemoteSigned

Install-Module -Name ExchangeOnlineManagement

connect-exchangeonline

Set-DistributionGroup -Identity "Group Identity" -ManagedBy "User1" -BypassSecurityGroupManagerCheck

Note:

Group Identity use your DL name

User 1: Use the new DL owner email ID