Unable to set site collection admin with Set-SPOSite

[Olf]

Hi,

in our SPO tenant we have a couple of site collections that no global admin account can access.

I tried making a global admin account of ours the site collection admin by using Set-SPOSite.

Strangely enough, I'm getting an error stating: "Set-SPOSite: The site at url [...] was not found."

However, when I open the corresponding url in the browser I'm not getting a message that the site was not found., 403 I believe. Instead I'm seeing a completely blank page but in the url address bar it says: "/_layouts/15/AccessDenied.aspx?[..]"

Next, I executed "Get-SPOSite | Select LockState, Owner".

The site is not locked but the owner is an account that I've never encountered before: ylo001\_spofrm_145_11106

The affected site collections do not appear in the admin center under sites or in the recycle bin.

Does anybody have an idea how I can rectify this situation?

Thanks for your help.

[#2]

Is this, by chance, a site linked to a Group? If so, what you can do is just add the user as owner in the Group and wait just some time so changes are propagated to SPO.

[#3]

@Olf try running below commands and see if the site will get displayed

Get-PnPTenantSite -WebTemplate SITEPAGEPUBLISHING#0

Get-PnPTenantSite -WebTemplate GROUP#0

[#4]

Unfortunately, the affected site collections do not have any of those templates.

Moreover, running Get-SPOSite | Select-Object Template shows that the problematic sites do not even have a template associated with them. Running the same cmdlet for any regular site will show me its template. I will try to create a MS support ticket.

[#5]

Hi Florian Hein,

Please try the below steps:

1. Run 

Get-sposite and Note the URL of the affected Site collection.

2. Run

Get-SPOSite "URL NOTED IN STEP 1" | Set-SPOSite -Owner "EMAIL ADDRESS of the desired OWNER" -Confirm

Please mark the question answered if steps above helped...

[#6]

Hi Florian Hein,

Please try the below steps:

1. Run 

Get-sposite and Note the URL of the affected Site collection.

2. Run

Get-SPOSite "URL NOTED IN STEP 1" | Set-SPOSite -Owner "EMAIL ADDRESS of the desired OWNER" -Confirm

Please mark the question answered if steps above helped...