Fix "Sorry, You don't have access" Access Denied Error on Save Site as Template in SharePoint Online

Problem: Getting "Sorry, You don't have access" access denied error when trying to save site as template in SharePoint Online site from URL: https://crescent.sharepoint.com/_layouts/15/savetmpl.aspx

Solution: To fix this problem, we need to enable custom scripts. Here is how to fix the access denied error on Save Site as Template.

• Login to SharePoint Online Admin Center
• Click on Settings from the left navigation >> Scroll down to "Custom Script" section
• Set "Allow users to run custom script on personal site" and "Allow users to run custom script on self-service created sites" options. 
  
• Click on "OK" to save your changes.

However, this change may take up to 24 Hours to reflect. To enable scripting on a particular site collection immediately, use this PowerShell script in SharePoint Online Management Shell.

PowerShell to Fix SharePoint Online Save Site as Template Access Denied Error:
Use this PowerShell script to immediately fix the access denied error on save site as template.

#Config Parameters
$AdminSiteURL="https://crescent-admin.sharepoint.com"
$SiteURL="https://crescent.sharepoint.com"

#Get Credentials to connect
$Cred = Get-Credential

#Connect to SharePoint Online Tenant Admin
Connect-SPOService -URL $AdminSiteURL -Credential $Cred

#Disable DenyAddAndCustomizePages Flag
Set-SPOSite $SiteURL -DenyAddAndCustomizePages $False

Please note, the change by PowerShell script can be overridden in the next 24 hours, If the settings don't match! So make sure you have same settings (either disable or enable) both in PowerShell and in SharePoint Online Admin center "Custom Script" settings.