Hello,
We are hosted by Microsoft for our email. We have been on Outlook 2010 for a couple of years without any issues. I have proxy access to two other mailboxes for support purposes. Up until last Thursday, when I replied to an email in the support mailbox, the default FROM address was the address for that mailbox. Last Thursday, something changed somewhere so the default FROM address is now my personal mailbox. I do have access to send mail from the proxied accounts so it isn't a rights issue. I am able to change the FROM address each time I reply but this is cumbersome. My personal email should never be going out on replies but remembering has been a chore since it always used to work correctly.
Our helpdesk had me install a plugin called unisend which did fix one related issue but didn't correct the issue I'm experiencing. I have talked with our senior network engineer and mail administrator and both confirm they did not make any changes. I did upgrade my PC to Office 2013 in hopes that something became corrupted with my installation (that the upgrade would fix) but that did not correct the problem.
Ideas?