2 missions (to different places), just flying along on a route then it just stopped working. Looking in logs it shows this:
{14:04:11} Webserver request failed: code 400, details 'I3QlK59NybjDMpPVG5+kQ7vAySP4iDG0kpFBRHdH//....'
{14:04:11} WebRequest: StatusCode=400; Request-Tag=gxjrdk5fkg6a
{14:04:11} Disconnect: type=4&reason=Hyperspace. Reason: Maximum distance exceeded&primary=
{14:04:11} Disconnect requested in EnterLocation::Advance
{14:04:11} Cancelling request 103
Bit random since the jump that was failing was well under my maximum range (and was plotted by the route finder anyway)
Resolved it by jumping to somewhere that was 1.19ly away, then I could do long jumps again. Strange.