site collection administration missing

[BatMon164]

Hi, when I try to use appregnew.aspx  on one of my work colleagues SharePoint site,  I keep getting an error message saying ACCESS DENIED. I dont see Site Collection Administration section either. I am listed in Owner group and have Full Control. I am able to see the missing section on the other SharePoint site, which I created.  Can anyone advise, please?

[#2 · Accepted solution]

@BatMon164 You need to be in the site collection administrators to access this page (Owner in not enough). You need to ask your M365 admin to add your name or the owner group in the site admins permissions from the SharePoint Admin Center.

[#3]

@Martin Coupal Thanks! it worked!