If still you can't upload logo following the logo requirements, you may try uploading logo using a private browser. You may use either of the following shortcut keys:
Google Chrome, press CTRL + Shift + N
Mozilla Firefox: press CTRL + Shift + P
Internet Explorer: press CTRL + Shift + P
Safari: press Command + Shift + N
If it works fine using a private browser, you may need to clear the cache of your regular web browsers. Also, switching to another supported browser can help us narrow the cause of this unexpected behavior.
Don't hesitate to update us with the result by adding a comment below, we're always here to help. Have a great day ahead!
As long as you've met the logo requirements mentioned by my colleague @Angelyn_T, you should be able to successfully change your company's logo.
If you've already tried all the steps provided, I would suggest reaching out to our Online Support so they can further assist you with uploading the logo. This way, they can also check the root cause of why you're having issues with the upload.
I'll be here if you need anything else. Just hit the Reply button below if you have other questions. Have a good one.