Profile/API-Token: Authentication error (Code: 10000)

[cj11]

Same issue as this one:

Cannot create API token - Authentication error (Code: 10000)

When I navigate to https://dash.cloudflare.com/profile, I’m getting a red banner error across the bottom of the page that says: Authentication error (Code: 10000) Then, if I attempt to create an API token, I get a different red banner error: API Request Failed: POST /api/v4/user/tokens (500)

Authentication error (Code: 10000) in profile and
API Request Failed: POST /api/v4/user/tokens (500) when trying to create API-Tokens.

Tried different browsers on different locations, log-in & -out, private mode → no improvement

Seems to be a more or less common issue, as there is a significant number of similar tickets - without solution besides posting a ticket, though.

Any suggestions how to proceed?