Farrah Abraham, Maitland Ward Call BS on Sophie Rain's OnlyFans ...

OnlyFans model Sophie Rain shocked people with the claim she's made more than $40 million so far this year ... but 2 adult stars are saying her math is just not mathing.

Here's the skinny ... Sophie made international headlines when she said a boatload of money has been dropped on her this year thanks to OnlyFans ... claiming at least one fan tipped her $4 million!

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Farrah Abraham tells TMZ ... she is all about supporting other women on OnlyFans and in the adult-film industry -- but she just does not buy what Sophie is selling.

As far as Farrah is concerned … the over-the-top claim is just a publicity stunt to grow SR's socials and OFs following -- which to be fair, are very impressive with millions of followers apiece.

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And FA told us Sophie's recent virginity boast to TMZ is another eye-roll fib to sell subscriptions.

Porn star Maitland Ward is also calling BS on Sophie's alleged income, telling TMZ ... to pick such an unbelievable number was not a wise choice ... 'cause it makes people immediately suspicious. That said, if it is true, MW says good for you!

TMZ.com

In her opinion ... MW thinks it's not cool that Sophie is misleading younger women would-bes who think they can jump on OFs and make a ton of money ... like an alleged virgin without a single sex scene.

Sophie's alleged massive income aside, Maitland tells us ... OnlyFans is hurting the traditional porn industry, 'cause legit fan-favorites are fleeing for more control over their content ... and income.

We reached out to Sophie for comment on the pushback ... she says “I have shown video proof on Twitter and I have no reason to lie. I wish success for their careers and they are more than welcome to personally contact OnlyFans to verify the legitimacy of my numbers.”