I am unable to access exchange online via powershell anymore. it has been about 2 or 3 months since i have tried but this used to work with no issues. 

I have tried connecting 3 ways, all of which fail with the same error

#1

$UserCredential = Get-Credential

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection

Import-PSSession -Session $Session -DisableNameChecking

the progress bar comes up, it says importing and counts up to 6 or 700 commands as expected then the unexpected error message:

Import-PSSession : Data returned by the remote Get-FormatData command is not in the expected format.

After that, none of the commands work - example Get-Mailbox 

#2

Connect-EXOPSSession -UserPrincipalName ******@x.com

same deal. same error

Import-PSSession : Data returned by the remote Get-FormatData command is not in the expected format.

At C:\Users\x\AppData\Local\Apps\2.0\A53V0WOT.PE1\6Y7OL9NA.H46\micr..tion_1f16bd4ec4c2bb19_0010.0000_673f37

c317fb5976\CreateExoPSSession.ps1:311 char:40

• ...      $PSSessionModuleInfo = Import-PSSession $PSSession -AllowClobber

+                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : InvalidResult: (:) [Import-PSSession], ArgumentException

    + FullyQualifiedErrorId : ErrorMalformedDataFromRemoteCommand,Microsoft.PowerShell.Commands.ImportPSSessionCommand

#3

Connect-ExchangeOnline -UserPrincipalName ******@x.com -ShowProgress $true

same deal. same error

The module allows access to all existing remote PowerShell (V1) cmdlets in addition to the 9 new, faster, and more reliable cmdlets.

|--------------------------------------------------------------------------|

|    Old Cmdlets                    |    New/Reliable/Faster Cmdlets       |

|--------------------------------------------------------------------------|

|    Get-CASMailbox                 |    Get-EXOCASMailbox                 |

|    Get-Mailbox                    |    Get-EXOMailbox                    |

|    Get-MailboxFolderPermission    |    Get-EXOMailboxFolderPermission    |

|    Get-MailboxFolderStatistics    |    Get-EXOMailboxFolderStatistics    |

|    Get-MailboxPermission          |    Get-EXOMailboxPermission          |

|    Get-MailboxStatistics          |    Get-EXOMailboxStatistics          |

|    Get-MobileDeviceStatistics     |    Get-EXOMobileDeviceStatistics     |

|    Get-Recipient                  |    Get-EXORecipient                  |

|    Get-RecipientPermission        |    Get-EXORecipientPermission        |

|--------------------------------------------------------------------------|

To get additional information, run: Get-Help Connect-ExchangeOnline or check https://aka.ms/exops-docs

Send your product improvement suggestions and feedback to ******@service.microsoft.com. For issues related to the module, contact Microsoft support. Don't use the feedback alias for problems or support issues.

Import-PSSession : Data returned by the remote Get-FormatData command is not in the expected format.

At C:\Program Files\WindowsPowerShell\Modules\ExchangeOnlineManagement\1.0.1\ExchangeOnlineManagement.psm1:454 char:40

• ... oduleInfo = Import-PSSession $PSSession -AllowClobber -DisableNameChe ...

+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : InvalidResult: (:) [Import-PSSession], ArgumentException

    + FullyQualifiedErrorId : ErrorMalformedDataFromRemoteCommand,Microsoft.PowerShell.Commands.ImportPSSessionCommand

At this point effectively unable to admin exchange online via powershell. Anyone have any ideas?