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:

A non-admin user can create no more than 250 resources in Azure AD. That is one of the many Azure AD service limits and restrictions. A “resource” can be an app registration, an Office 365 Group etc. But I would like to discuss Groups more in detail.

Imagine the following scenario: Your organization has disabled Office 365 Group Creation. Only IT can create new groups. A service account has been set up for creation of team sites. The application permissions are “binary”, either everything or nothing: Group.ReadWrite.All. This service account will hit the limit very soon.

In SharePoint 2010 if CMSSiteManager.js library is loaded besides jQuery, then much of stuff stops working. The reason is that the dollar sign ($) is used in cmssitemanager.js as well which conflicts with jQuery. Mostly it appears on pages where you load jQuery and have an image library with thumbnails. To avoid this, just replace all $ with jQuery in your custom scripts. A more crazy situation is when avoiding $ isn’t enough. It is when you load jQuery to page head automatically on all pages. The Asset picker (AssetPortalBrowser.aspx) invokes $ itself and gets with jQuery in conflict without you write a single line of custom javascript code. You usually get the following error: