Re: APCC GPS Error
UpdateLocation. Index and length must refer to a location within the string. Parameter name: Length.That means there was an error parsing the response from the device. It could be that the data received was corrupted, or in an unrecognized format. If the error persists, it could be device's response is not in a standard format, or maybe the wrong baud rate is selected.
Author of PEMPro
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver