Before Napoleon sent troops to Russia, was he not blocked by Prussia, Austrians, or other countries? Did his neighbors allow him to pass without a fight?
The problem was that Napoleon barely listened to others.
Any history professor, especially a military historian, will recount the fiasco of King Charles XII of Sweden's invasion of Russia and advise against it. And that invasion wasn't even a century ago! Worse still, Napoleon even read the accounts, but still failed...
Yes, in the 17th century, the Polish-Lithuanian invasion was half successful, but then Russia fell into utter chaos – a civil war – and eventually Poland had to give up, having surpassed its peak.
Poland-Lithuania at the beginning of the Polish-Russian War in 1605
1618/9 Polish-Lithuanian at the end of the Polish-Russian War
But as in the case of a foreign invasion, Russia fought against Western invaders as a single person, and at the same time a pesky Roman Catholic, Tsar Alexander I's position has never been stronger.
Tsar Alexander I, reigned 1801-1825
In addition, the only foreigners who supported Napoleon were poles in the Grand Duchy of Warsaw. When Napoleon invaded, at least the Lithuanians were sympathetic.
Grand Duchy of Warsaw 1809-1815
It is true that many Dutch, German and Italian soldiers fought in Napoleon's army, but because they had to do so, not from the heart. Even in Italy, there are people who are unhappy with the annexation of France.
Yes, Prussia supported Napoleon— I suspect it was reluctant — and Austria did. The Grand Duchy of Warsaw, on the other hand, was a fanatic. There is no doubt that a clever observer like Metternich, the Austrian Chancellor, must have doubted the success of the French invasion, but he never said so.
Yes, the Principalities of Austria, Prussia and Warsaw allowed Napoleon to cross... If you do stop or even hinder Napoleon, he will invade you anyway.