This is a complicated question that relies on the US-India Tax Treaty to determine whether the income is taxable to the US or to India. The relevant provision is likely Article 15 on Personal Services.
It seems plausible that your business is personal services, but that's a fact-driven question based on your business model. If the online training is 'personal services' provided by you from India, then it is likely foreign source income under the treaty. The 'fixed base' and '90 days' provisions in Article 15 would not apply to an India resident working solely outside the US.
The question is whether your US LLC was a US taxpayer. If the LLC was a taxpayer, then it has an obligation to pay US tax on any worldwide income and it also arguably disqualifies you from Article 15 (which applies to individuals and firms of individuals, but not companies). If you were the sole owner of the US LLC, and you did not make a Form 8832 election to be treated as subject to entity taxation, then the LLC was a disregarded entity. If you had other owners, and did not make an election, then you are a partnership and I suspect but cannot conclude that the treaty analysis is still valid.
So this is fact-dependent, but you may be exempt from US tax under the tax treaty. However, you may have still had an obligation to file Forms 1099 for your worker. You can also late-file Forms 1099 reporting the nonemployee compensation paid to your worker. Note that this may have tax consequences on the worker if the worker failed to report the income in those years.