Have a bit depth (or color depth) of 24-bits or less.
Use the standard RGB color space (RGB).
The shape of the logo should also be square, instead of a rectangle.
In the meantime, let's try to upload your logo from the Custom style section. Let me guide you how.
Click the Gear icon and select Custom Form Styles.
Select the invoice template to open it.
Click Make logo edits under the Design tab.
Click Show logo.
Hit Done.
Also, let's try to upload it to your company settings. From there, it will show automatically on the form template. Go the Gear icon, click Account and Settings. On the Company tab, tick the box that says logo. On the pop-up, browse to open the logo. Then, hit Save and Done.