Using Classic Outlook on Windows for personal email, calendar, and contact management
Hello Anthony,
I'll need to check a few things first to figure out exactly what is causing these two problems. Getting a sending limit error on your very first email usually happens if the account sending reputation dropped from the previous mass email you mentioned or if there was unauthorized activity overnight.
Have you looked through your Sent folder to make sure there are no random emails you didn't personally send? I also need to know if you have a mobile phone number linked and verified on your Microsoft account since that heavily affects your account sending limits.
Regarding the Office app issue on your desktop, Microsoft license syncing can definitely get messy when a new 365 trial is introduced on a second computer with the same email.
What exact standalone version of Office did you originally pay for on that desktop? I just need to know if it is 2016, 2019, 2021, or something else so we can check why your desktop is suddenly pulling the new laptop's trial license instead of your permanent one.