[AirSync] error encountered

I downloaded the latest version of eM Client today to try it out. I am on the 30-day trial to see if I want to keep using it. My work email account is on Office 365, and I set it up with the Outlook.com option without any trouble. After my first work email send, a box popped up with the following error message:
"16:54:40 Work Email [AirSync] MailClient.Accounts.MailSendException: Sending email “Re[2]: Large images to print for a class” failed with error: MailClient.Protocols.Common.HttpResponseException: Exception_WasThrown, MailClient.Protocols.Common.HttpResponseException
at MailClient.Protocols.AirSync.Protocol.ActiveSyncCommandRequest.GetResponse(CancellationToken cancellationToken)
at MailClient.Protocols.AirSync.AirSyncFolderSynchronizer.<>c__DisplayClass11_0.b__0(WorkerStatus status, CancellationToken cancellationToken)
AccountId = b9289013-8f78-4d0a-b85f-16e92a8e552b
AccountName = Work Email
Item.Type = MailClient.Storage.Application.Mail.MailItem
UniqueItemId = null
mail.Subject = Re[2]: Large images to print for a class
mail.MessageId = [email protected]
GUIStatus_Exception_Reported = True
"

The email actually sent, but I don’t know if there’s a problem lurking behind the scenes.