"You must be a WPM administrator" but I am a WPM administrator

In all humor/irony, you probably need full manage nodes admin. another need for needing granular permissions models.    

I've noticed a similar issue though, maybe jiri.tomek‌ can explain or help. I always found WPM permissions to be wonky at a minimum.

It turns out that the issue here is that I was inheriting admin permissions as part of an AD group. Apparently WPM doesn't recognize that properly for this purpose. Once we added my AD account specifically within Orion, the problem went away.

I've requested that Solarwinds support open a bug report on this.

So you added your individual AD account as a user?

That doesn't sound like an administrative solution as much as a bug.    

Correct. I edited my post (probably while you were typing yours) to note that I requested that SW open a bug report on this.

I tried all of the suggestions listed here, as well as opening a case, with no success.

Then, I was reading through discussions under Web Performance Monitor, which pointed me to look into the Orion database.

I originally looked at [Solarwinds_APM].[dbo].[Accounts] to compare my setting with other admins who did not have any issues, and found no difference.

I then started looking at the SEUM tables

I went into the database under the following table [Solarwinds_APM].[dbo].[SEUM_WebUserPermissions]

When I located my name, I found PermissionValue was set to ‘False’.

When I set to ‘True’, I was able to open WPM with no problem.

I did not find this solution referenced anywhere else, so I wanted to share.

It's been over 3 years now and this bug is still not fixed Admins rights are not inherited for AD Group and adding individual users or creating local SW accounts is not a solution.

Another year... still a problem.

In my SEUM_WebUserPermissions table my my accountID has just one row. The PermissionName is "SEUM.SUEMAllowAdmin" is and the PermissionValue is already equal to "True." Maybe something else has changed in the past couple of years.