McKesson has announced that there will be downtime for communication on Saturday Sep 20.
Here is the announcement they sent to us.
During our weekly scheduled maintenance window this weekend, there will be an interruption to our communications impacting AS2 and FTP (including SFTP). We anticipate the communications outage to take place between 10pm Pacific Saturday, September 20 and 1am Pacific Sunday, September 21. During that time we will be unable to send or receive data. Data outbound from McKesson will be held and sent after communications are restored. If you experience failures in delivering files to McKesson or retrieving files from McKesson’s servers during that period, please retry after the planned outage window (after 1am Pacific, Sunday September 21).
If you have any questions feel free to contact the support team.