Snappymail icon no longer shown on browser tab after upgrading to 2.38.0

[europacafe]

Before the 2.38.0 update, the Snappymail icon, which is shaped like an envelope, appeared on the MS Edge tab, but it has since disappeared. This could be related to the update, or there may be steps I need to take to restore it. Thank you.

[europacafe]

Any idea?
I've set the avatar url, under snappymail admin page, to my web server where the logo is stored. It worked with previous snappymail versions, but not with the latest one.