@Volvass80 The internet speed doesn't have be fast. The connection just has to be stable and the ping/latency shown by Vdash should be in the green range all the time.
I see two potential problems.
Your charger is not the best choice for software operations as it not only has a slightly too low power output. It most probably has no filter on the power outlet, so it sends interferences to the car. But if you attach both cables directly to the battery most of those interferences should be filtered out by the battery.
Your adapter is most likely the real problem here. A price tag in the 30-60 Euro range is an almost 100 percent guaranty to get a low quality device these days. Good quality DICE clones with original M32C chipset start at around 100 Euros. And good Mongoose JLR Pro/Super J2534 with the original Atmel chipset are even more expensive.
D5T5 and some of their partners offer to rent an adapter. So you don't need to spend that much money for a single operation. Your Scanmatic clone is good enough for diagnostics and service functions. It's just not good enough for configuration changes and cloning.
You can try to get a refund by creating a support ticket here chose VDASH-Refunds.
