Well, that's a worry because support is telling me the opposite, and they're seeing more of these tickets coming in. The RBAC Diagnostic test can't find the parameter 'EwsAllowedAppIDs' that can't be expected right? I'll DM you the Case number.
There are no custom roles involved. The account has the Exchange Administrator role, and I even added it to the Organization Management role group just to rule out any RBAC issues. I'm using PowerShell 7.6.6 with Exchange Online Management Module 3.10.1. I tested access to other tenants without issues.
I also ran the EXO RBAC Test User Diagnostic, which returned the following result:
"Couldn't find a management role allowing access to cmdlet 'Set-OrganizationConfig' with the parameter 'EwsAllowedAppIDs'. The parameter appears to be mistyped."