Outlook has a number of common issues that can be resolved in some simple troubleshooting steps. Try the things below before escalating to Help Desk if you'd like to resolve your issue quickly.
Sending from another address
Start a new email
Click Options
Click From
If you don't see the From button, you may need to click the down-arrow to expand the options on your menu bar for it to appear.
A new field will appear next to the send button called From
Click the new From button
Click Other email addresses
Type the address you wish to send from or click From to look it up in the address book
You will need to have permissions to send on behalf of the user / email address that you select.
Troubleshooting:
Is Outlook the Issue?
The very first thing to do is confirm if the problem is your Outlook software, or a problem with the email server. You can do this by checking your email in the Outlook Web App (OWA), which is a browser-based email client that most directly reflects what is in your email according to the email server. You can do that by going to https://outlook.office.com and signing in with your otc.edu email address and password. If your email looks fine there, we know the problem is with Outlook and you should follow additional steps below regarding your particular issue. If the problem exists in the OWA, we know the problem is more likely with your mailbox on the server, and you should contact the Help Desk.
Outlook isn't updating with new email, or can't send/receive emails
Check the bottom of the Outlook window. Is it asking for a password or does it say it's Disconnected?
Click on Need Password or Disconnected
You'll get a prompt asking for your username and password. Provide them.
Check the Remember my Credentials box.
Click OK
If this does not resolve the issue, try resetting your Microsoft Credentials and then restart Outlook.
If resetting your credentials doesn't resolve the issue, contact the Help Desk.
Outlook will not start or hangs at loading screen
Open Outlook in safe mode:
Close all instances of Outlook in task manager
Open a run box - right-click start button and click Run
Type "Outlook.exe /safe" and hit Enter
Click OK to choose the profile
After Outlook opens, close and re-open normally
If Outlook will still not open:
Close all instances of Outlook & Teams in task manager
Go to Mail in Control Panel
Click Data Files
Highlight the account and click Open File Location…
Show file extensions
Rename the OST to .old
Reopen Outlook
Additional Troubleshooting
There is an additional step you can do to rule out your Outlook profile being corrupt as the source of the problem. You can create a new Outlook Profile to test. If the new profile works fine, you know your old profile was the problem.
Note: Items such as your viewing pane settings, signatures, and other personalized settings reside in your Outlook profile. Creating a new one means you will need to configure these items as if you were setting up your email for the very first time.
Close Outlook.
Search for the Mail Control Panel item:
Click Show Profiles
Click Add
Give your new profile a name. This name is for your reference so you can name it whatever you want.
You will be prompted for Auto Account Setup. Click Next.
After it sets up your email, click Finish.
Under the radio button for Always use this profile, click the dropdown menu and select your new profile.
Click OK.
Reopen Outlook. After it sets up your mailbox as if for the first time, see if the problem is resolved.
(Optional) If it is not, you can always repeat steps 1-3, and then step 8 to set your profile back to your original named "Outlook".
Undeliverable Reply to an OTC Email Address
You may receive an undeliverable notification if an address that Outlook has cached is corrupted. To correct this remove the entry from your cache.
Start a new e-mail
Begin typing the address in the To field
When the address appears in the autocomplete pop-up, click the X
Continue typing the complete address or look up the address in the address book.
See more about Common Undeliverable Mail Errors or Undeliverable Errors using Send-As Another Mailbox
Error that the file you're attaching is bigger than the server allows
Messages sent through our email server must be a total of 150mb or smaller. Please check your attachment sizes. You may want to save your files to a OneDrive folder and send a link instead.