Update error code 30088-27 Office 2021 what to do to get corrected????

After installing build 16.0.17830.20166 this problem is not present anymore on my PC.

This is what I've done:

1. I turned on the automatic Office updates in File - Account - Options (as it's always been)
2. I opened an Admin Terminal session and copied and pasted this command:

"C:\Program Files\Common Files\microsoft shared\ClickToRun\officec2rclient.exe" /update user updatetoversion=16.0.17830.20166

A regular Office update window opened and I just waited 'till the end and then closed it.

No more error now when I check for Office updates.

I hope it does the same for you.

I tested using two methodologies.

I took a device inside my network behind Firewalls and Proxies and it failed.

I took the same device and plug edit into a home network without firewalls and Proxies and it worked.

We then used Fiddler and Wireshark to analyze the traffic and found that connections to Microsofts CDN when we invoked the Clicktorun were not using the WinInet Proxy.

Our Proxies were configured for Authentication for Microsofts CDNs. When we disabled Authentication, as is required for WinHTTP Proxy, the Click to run worked and our Office started to update. We've had 4000 Systems stuck on June's update for 2 months, As of today we've been able to patch 3000 systems with this firewall/proxy change.

This is not the kind of configuration the ordinary user would have here. I would assume most users here are on a home network and not an enterprise environment as you describe. Also, besides the fact that how does this explain some of the users having fixed the error, me included by other implementations mentioned here? Your knowledge is commended but I would be surprised that ordinary users will need to implement this type of change.

Thanks, but I'm still lost as to how to proceed.

I tested using two methodologies.

I took a device inside my network behind Firewalls and Proxies and it failed.

I took the same device and plug edit into a home network without firewalls and Proxies and it worked.

We then used Fiddler and Wireshark to analyze the traffic and found that connections to Microsofts CDN when we invoked the Clicktorun were not using the WinInet Proxy.

Our Proxies were configured for Authentication for Microsofts CDNs. When we disabled Authentication, as is required for WinHTTP Proxy, the Click to run worked and our Office started to update. We've had 4000 Systems stuck on June's update for 2 months, As of today we've been able to patch 3000 systems with this firewall/proxy change.

Thanks again, but I'm really not sure re the terminology you're using nor can I implement the instructions (in the least).

Again, I am curious as to how this can be the issue since some users appear to be totally unaffected while others can't seem to resolve it no matter what they do and reverting back to an earlier build (prior to the change) produces the same result.