This happens because Outlook sometimes blocks unknown attachments to safeguard users’ data. The error 0x800CCC13 in Outlook appears when trying to send an email. The error message indicates a connection issue but it can also occur due to other reasons, like incompatible add-ins, virus or malware intrusion, or bad sectors on the drive.
If you need to increase the number of this limit try the next resolution. The maximum number of recipients for an individual email through USNH IT mail servers is 300. Step 1 - Follow these instructions to uninstall your Office applications. If you manually type in the secondary connected account email address in the "From" field, the email is sent as "On behalf of" your primary Outlook.com account. You might need to set Windows Update to automatically download and install recommended updates.
Follow these steps to let Outlook diagnose and fix errors in your Outlook mail profile that might be causing the issue. You can create a new Outlook Data File and drag the items in the Lost and Found folder into the new data file. After you've moved all the items, you can remove the Recovered Personal Folders (.pst) file, including the Lost and Found folder. To create a new Outlook Data File, go to Create an Outlook Data File. The steps to access the repair tool vary depending on your operating system. If you can't open Outlook, or Outlook disappears or crashes, one of your add-ins may be to blame or you may need to update Outlook.
To install the latest Windows and Office updates, click the link below. Not something you want to take on lightly, but sometimes you have to. Similar to our earlier suggestion of repairing Office (see #3 Repair Your Microsoft Office above), perform the same steps except choose to Uninstall. Be aware that you may need your product key if you received one. Microsoft has its own tool for methods to stop Outlook crashing automatically scanning and correcting Office when things go awry. You can read about it and then run the Microsoft Support and Recovery Assistant to see if that helps.
Once the PST file is repaired, you can import the repaired PST file into a new or existing Outlook profile to restore and access all mail items. In the Folder Pane, you might see a folder named Recovered Personal Folders that contains your default Outlook folders or a Lost and Found folder. Although the repair process might recreate some of the folders, they may be empty. The Lost and Found folder contains any folders and items recovered by the methods to stop Outlook crashing repair tool that Outlook can't place in their original structure. Moreover, this tool can quickly recover email messages, calendars, tasks and other data from corrupted PST files. It also offers a filter option