The allies experienced a ton of supply issues during the war.

The most prominent example would be the Normandy outbreak and further on into the summer campaign. The allies broke out and overwhelmed the German forces and forced them back. But the only allied port available was Cherbourg. That means for all the troops being put into the field, Cherbourg was the only port in which they could be supplied from. Allied forces eventually went further into France and the further they went the harder it got and they soon slowed down. The Germans call this the “miracle in the west” and soon the entire allied army was stopped outside of Germany itself. But the allies had some good news, Antwerp had been taken and this was a major port near the frontline. But the issue was that the sheldt estuary still had German troops on it, thus causing the port to be unusable until these Germans were kicked out.

So a plan was made to land paratroopers near some bridges in holland. This would threaten to entire the Germans in the Estuary forcing them to withdraw allowing allies to use the port and continue the attack, this was Market Garden and it didn’t do well.

That’s just one prominent example of supply lines, it’s very similar to the Germans as in the further they got, the harder it became to supply them. But the major difference was the English Channel was nearby and England itself was there, so all of the supplies the allies had stored up just needed to be transported. All that was needed was a port to use them. Another fact that the allies had going for them was the amount of trucks that they had, which was a lot, compared to the Germans who were lacking trucks. Allied forces also could use railways in which the Germans were constantly having theirs destroyed from partisans or bombardments. This was big for Germany because they relied on rails a lot more than the allies because they themselves were lacking oil, you could have 10,000,000 trucks, but if you have no gas and oil, you’re out of luck.

Also here’s one funny fact about allied supply lines. Between when Paris was liberated all the way to about February, there was an average of 15,000 American deserters in Paris and these troops would steel things like fuel, food, and even weapons and sell them off to either French civilians, or allied units and troops.