To be fair, accepting contributions from outside folks requires a well-designed legal framework. Otherwise it's a legal mess. It could be that they just don't have it in place for folks outside the company.
Discussion
Then it’s not open source
Sure.
It might be open source, just not free software
SQLite is open source, right….?
It also does not accept contributions also.
Open source defined by the Open Source Initiative does not include the right to force maintainers to accept your contribution.
That’s called “open contribution”
Ok, try to reproduce this 😄
note1wlfzc37cvnmxthah6jyflpl0l5mqg703uz60gn8f0v20n5gtfurqa5as00
Yeah, not claiming it’s open source, but also open source does not mean contributions need to be accepted