You’ll need your email account credentials, like the username, password, and configuration settings to re-add the account to Outlook. This helps Outlook re-establish a connection with your email server, fixing any connection problems. If Outlook couldn’t fix the issues with your email account, consider removing and re-adding your account to the app.

Select Repair on the screen that opens and follow the on-screen instructions.

Select your email account in the Email tab and choose Repair.

Choose Account Settings > Account Settings in the pane on the right.

Luckily, Outlook includes a repair tool you can use to fix all the email accounts you’ve added to the app. If your email account with Outlook has problems, that can cause the app to malfunction. Resolve Server Error by Repairing Your Outlook Email Account

The Work Offline button won’t be shaded anymore, which indicates the feature is turned off.

Select the Send/Receive tab at the top.

In this case, turn off the offline mode, and Outlook will be back online. However, if you’ve enabled this mode, that may be why the app fails to connect to your email server.

Outlook offers an offline mode that you can use to work on your emails while being disconnected from the internet. You can either fix this yourself or seek the help of your internet service provider. If the site fails to load, you have a connection problem.

Outlook 2013 online