Gallic Royal Forces are Hostile to Every Single Sirian Faction, and also:
' Wrote:- Most Sirian factions have been repninjed hostile to the GRN.
You said You have IMG ID, and your Rep gets reset to Hostile as soon as you Undock. Which means your ID has a Repfix against GRN/GRP. There is no reason behind being Neutral to Gallic Lawful Factions either, because as I assume, You want to Trade in Gallia, with a Sirian Ship And a Sirian ID. Royals won't like that Even one bit, I don't see why shouldn't they shoot you!
I suggest you either pick a Sirian Trade Route, suitable for an IMG (Which are Far more Profitable than Gallic ones), or Make a new char, Get a Gallic Corporation ID and a Gallic Trade Ship.
P.S: If you're doing this to be able to do the Military Vehicle run through Gallia, Don't waste your time. That route got nerfed long ago. FLCompanion tells you it's there and has a nice profit because it reads your game .ini Files, while the Prices are changed Server-side.