Here’s how you can fix it.
Outlook Meeting Response Options not visible
Instead of seeing Accept, Tentative, or Decline options for the meeting invite in Outlook, a user may find only ‘No Response Required’ option displayed in the Respond section of the ribbon. This occurs mainly due to the modification of data under a Windows Registry key. To fix this, you’ll be required to change the value of DisableResponseButtons to zero (0) in the non-policy section of the Windows Registry. Open Registry Editor by pressing Win+R in combination to open the ‘Run’ dialog box. Type ‘Regedit’ and press Enter. When the Registry Editor opens, go to the following location – Scroll down to locate ‘Software’ folder. When found, click it to expand. Next, scroll down to ‘Microsoft’ and then, Office > 16.0 > Outlook > Options > Calendar. The path (16.0) depends on your version of Office. Here, switch to the right pane of the Registry Editor window and look for the following entry – DisableResponseButtons.
Double-click this entry to open the Edit String box. In the Value Data Field of the box change the value from 1 to 0.
Close the Registry Editor and Restart Outlook. Your problem should have been resolved by now and you should be able to see Accept, Tentative and decline options under change Response control of Outlook.
