I get the same problem if ONE specific security is included in the selection. In my case it is a muni bond. That security has a made-up ticker and should not associate to anything in the Morningstar x-ray universe. I have other munis with made-up tickers that are not a problem. I have tried changing the name and the ticker with no positive effect. Baffling
I identified the problem security by trial and error. The SAML error only showed for one investment account. From there I selectively added and dropped securities until I id’ed the troublemaker.