Sunny Island F158 Error

midijeep

I get an error with the Sunny Island 6048 - F158 error code; the Sunny Island is advising there is a voltage source besides itself on its output side (AC1).
The system consist of a SMA SI 6048. Midnite Solar MNE250SMA-AC-Single E-Panel & Midnite Solar AutoTransformer MNX-240.  The Sunny Island when started keeps giving a F158 error then goes in standby mode.  I don't know where the the other voltage source is coming from.  There is a SunnyBoy 3000TL-US-22 included in the system.  Also a critical loads panel.  I  have turned off the critical loads panel but the error persist.
Some things I have tried:
1) F158 rror happens when when every component is on i.e. Autoformer, SI, & E-panel with the Critical load breakers turned off.  2)  if I keep the critical load breakers on I get the same SI error message but the Autoformer keeps tripping.

I can bypass the Autoformer and SI via E-panel to allow the critical panel to run and allow the SunnyBoy to run.

Any ideas what may be causing the AC1 detecting another voltage source?