Recently VMware by Broadcom made a change to the way that vSphere updates are downloaded for their products. You may find that when you try to update you see errors.
This is because not only has the URL changed for the download but you also need to insert a download token that is generated under your accounts entitlement. Meaning you can only get the updates you are entitled to.
You can see Broadcom’s documentation here: https://knowledge.broadcom.com/external/article/390098
You can either update this manually or through a configuration script that Broadcom supply but from experience the Broadcom configuration script works best.
Here’s the steps to follow to download and use the configuration script:
GENERATING AND DOWNLOADING TOKEN
1. Log into the website https://support.broadcom.com using the account that has the vSphere entitlement. If this account doesn’t yet have an account set one up for it.

2. Scroll down to the quick links section and click “Generate Download Token”

If you don’t see the Generate Download Token section then you are using the wrong account.
3. Click the drop down menu and select the Site ID then click Generate Token.

4. Once the token is generated you can click on the copy icon to copy the code to your clipboard.

USING THE BROADCOM CONFIGURATION SCRIPT
Prerequisites
In order to run this you will need the following:
1. To get the script, download the script file from: https://knowledge.broadcom.com/external/article/389276
NOTE: You will need to scroll down to the end of the post to download the script file.

2. Download the file and unzip the folder contents. I normally unzip it to the downloads folder so it can be easily be cleared up after.

3. IMPORTANT – Before you run the script take a snapshot of your current vCenter server!

4. Open Powershell 7 as an administrator and type
Get-PowerCLIVersion
This should show you the version of PowerCLI you have installed. This needs to be higher than or equal to 13.2.

5. Run the following commands:
Import-Module VMware.VimAutomation.Core
Then
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -Confirm:$false
These commands load the PowerCLI module and allows connection to vCenter with a self signed certificate without warning you.

6. . Browse to the folder where you downloaded the script file and run the script.
NOTE: If your system is setup to prevent scripts from running you may need to run the following first:
Set-ExecutionPolicy Bypass

7. At the menu, type 1 and press Enter.

8. When asked if this is a VCF deployment type Y for Yes or N for NO. In this case it’s an older vSphere setup so I type N and press Enter.
Enter the vCenter address as a FQDN i.e. vcenter.domain.local and press Enter
Enter the vCenter SSO username i.e. administrator@vsphere.local and press Enter
Enter the vCenter SSO password and press Enter
It should successfully connect to the vCenter server.
You get prompted if you want to connect to a second vCenter server. In my example there is only one so I type N and press Enter.
Press Enter again to go back to the menu.

9. At the menu, type 2 to enter your download token and press Enter. Enter (or paste) your download token and press Enter.
The token is then validated.

10. At the menu, type 4 and press Enter.
This will then update all the download URL’s in ESXi and vCenter.

11. Finally at the last menu type Q to finish and press Enter.

12. Checking for compliance\vCenter updates should now work.
Don’t forget to reset the Powershell Execution Policy if needed:
Set-ExecutionPolicy Restricted
and remember to remove the snapshot of vCenter and the downloaded script files once you are happy it works.