We have had troubles updating site icons in SharePoint Online. It might be related to one of the following:
- It occures only on hub sites
- The sites have a custom theme
The error message:
We experienced a problem updating the icon. Please try again in a few minutes.
But what I found is that there are two places where you change the site icon. If the first does not work, try the second one, that was what worked for us:
- Cog wheel -> Site Information -> Site logo
- Cog wheel -> Change the look -> Header -> Site Logo
Changing the logo through “Site Information”
Changing the site logo through “Change the look”
There are others who have encountered the problem. I hope the workaround I happened to find here can help.