Hi Thymen,
In order to find out the root cause of the issue, I need to collect the following information:
1. Are you using the Office 365 post-upgrade, which means the Outlook you downloaded is the 2013 version?
2. If you use the same account on these 3 PCs, please try using another account on the problematic laptop. This is to check if the issue is related to PC client.
3. If you use 3 different accounts on these 3 PCs, please use the problematic account on the other 2 PCs. This is to check if the issue is related to the account itself.
Your feedback will be highly appreciated.
Regards,
Allen Zhang