Thanks for taking the time to visit the Community. The problem you are experiencing when trying to add a logo has already been reported to our engineers. They are currently working on finding the cause so they can come up with a fix.
As a workaround, use other browsers like Chrome or Mozilla Firefox to add your logo. While the investigation is ongoing, I'd suggest contacting our phone support team so we can add you to the list of affected users. This way, we can notify you via email about the status of the issue.
Here's how to contact us:
Go to Help at the top and click the Contact us button.
Enter Support in the What can we help you with? box.
Hit the Let's talk button.
Select the icon for Chat or Get a callback.
I've also added a link you can use about how to customize logos, some FAQs, and remove them in your account: Logo.
The Community always has your back, so don't hesitate to let me know if you have any questions. Have a good one.