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

Just fascinating. For another data point (or two), I did exactly the same updates as you on two desktop (11 year old, i7)) machines both running W10 Pro and MS 365. Other than Windows Defender I have no other security software (nor anything unusual installed). Both machines connect via ethernet to a router which, in turn, connects to an ONT. I have changed nothing in my HW setup in a long, long time.

I have a 12 y.o. desktop machine (i5-3450), 16GB RAM, Win 10 Pro and Office 2021 Pro Plus, no security software othen than Windows Defender, the machine is connected via ethernet to a router that connects to the internet using FTTC (Fiber to the Cabinet) technology (copper to the cabinet, then fiber). I am Italian so I'm using win and office in Italian language, This is the "You're up to date" message (in Italian = "Il sistema è aggiornato").

So, when you manually check for updates in Office, you're now seeing the "You're Up to Date" Message?

Exactly

Just fascinating. For another data point (or two), I did exactly the same updates as you on two desktop (11 year old, i7)) machines both running W10 Pro and MS 365. Other than Windows Defender I have no other security software (nor anything unusual installed). Both machines connect via ethernet to a router which, in turn, connects to an ONT. I have changed nothing in my HW setup in a long, long time.

So, when you manually check for updates in Office, you're now seeing the "You're Up to Date" Message?

Exactly

I updated (elevated command prompt method) to Build 17830.20166 plus I installed the Patch Tuesday fare for Windows 10; KB5041580 and KB5042352.

Exactly the same for me, but in my case Error 30088-27 is gone.

So, when you manually check for updates in Office, you're now seeing the "You're Up to Date" Message?

I updated (elevated command prompt method) to Build 17830.20166 plus I installed the Patch Tuesday fare for Windows 10; KB5041580 and KB5042352.

Exactly the same for me, but in my case Error 30088-27 is gone.