Owners in a Microsoft 365 group cannot edit the calendar

[BoxOfFrogs]

We have an Office 365 Small business tenant.  There is a group that has been created, well call it "Accounting".  It has 7 members.  One of them, who is also an owner, told me if they try and move a meeting on the calendar they get a permissions error.  They cannot create one either, it is essentially read only.  

Working on this I have become more and more confused about things in general.  So this group was created a long time ago.   It has a SharePoint site and and email address.  The user in question added the calendar as a shared calendar.  As I said, he is an "owner" in the group.    When this group was created, was the calendar also created?  Are there different permissions that can be assigned to the calendar like other shared calendars (Reviewer, editor, etc.)?  If so, where would I find those?  Is this something I can only do via Powershell, or is it available in the GUI?

I guess my logic that if he is an "owner" of the group he should be able to anything with the Calendar is flawed.

[#2]

You have to clarify on "added the calendar as a shared calendar" part. If he's a member of the Group, the calendar will automatically appear in Outlook, so there should be no need to "add" it. As to creating events, he should be sending a meeting request to the Group' address, not creating events directly in the calendar.
To answer the other questions, there is no supported way to manage calendar permissions for a Group on a per-user basis, even though technically the same model as for regular mailbox calendars (and same cmdlets) is used.

[#3]

I'm sorry, I should have been clear on that. Yes, it just showed up in Outlook. But all he can do is see it. You mean to say there is now way to add/change an event directly on the calendar? I am in the same group, the calendar showed up in my Outlook client, I can do everything directly on the calendar. Now, I am the tenant admin, and I did create the group. But both he and I are owners. I find it very odd that an owner can't just create a meeting or event directly on the calendar.

To that point, there are events on this calendar. I have never added any events myself, so one of the other owners/users must have done it. Are you saying they did it via email?

[#4]

You can create events directly in the calendar, but that's not the correct way and requires permissions. Send a meeting request and include the group as participant instead.
Anyway, this doesn't address the original question, and an owner should indeed be allowed to add events directly, move them, etc. You can try demoting the user to regular member, then make him an owner anew, or even remove from the group first and add him back, hopefully this will "refresh" the permissions.

[#5]

Thanks Vasil.

Here are some new things I have discovered:

I noticed that Accounting was not listed as a group in the users online Outlook.
I removed the user from Accounting
I created a new Group, Test Group. I added the same user as a member. Almost instantly the group showed up in the Online Outlook. I didn't do anything at this point with the Calendar.
I then added the user back into Accounting as a member. Again, that group never showed up in Online Outlook.

I'm not sure how this group originated and can't seem to see any differences in the settings between the two. I am the Global Admin for the tenant. I am also an Owner of both groups.

My point is I think I need to fix this issue before I move on to calendars. How do you feel about this?

[#6]

I have a very similar problem.

I created a mail enabled security group to allow for use of the calendar with the group and none of the members or owners can see other members edits.

Did you find an answer to this?

@BoxOfFrogs 

[#7]

@ADoolittle_Zume well, sort of. Turns out that they're was a group, and a room with the same name. All the user had to do was add the room to his list. Then I opened the Room From Outlook calendar, went to properties and gave him edit rights. I never really did solve the problem of why it wasn't showing up as a group in Outlook for him. I'll probably visit that problem another day, just to learn how it works. But the room thing solved the immediate issue.

Personally, I find the room, group thing in 365 exchange to be very confusing.