Remote Server returned '550 5.2.3 RESOLVER.RST.RecipSizeLimit; message too large for this recipient'
Office 365 or Exchange online problem Remote Server returned '550 5.2.3 RESOLVER.RST.RecipSizeLimit; message too large for this recipient' Connect in your office365/Exchangeonlime with PowerShell Confirm the problem, Get-Mailbox | fl mailboxplan,maxsendsize,maxreceivesize If you have Get-Mailbox user@mailbox.com | fl mailboxplan,maxsendsize,maxreceivesize MailboxPlan : ExchangeOnline-1ab122338-4f1a-bac1-c28ff8a1234 MaxSendSize : 0 B (0 bytes) MaxReceiveSize : 0 B (0 bytes) Execute the command Set-Mailbox user@mailbox.com -MaxReceiveSi ze 55 MB -MaxSend Size 55 MB or Set-Mailbox user@mailbox.com -MaxReceiveSize 150MB -MaxSendSize 150MB To apply for all users run this. Get-Mailbox | Set-Mailbox -MaxReceiveSize 55MB -MaxSendSize 55MB