Can't get contract if working under brolly?

[LondonManc]

As per title, was anyone declined a contract, because working under a brolly? Did anyone strictly insisted on working via LTD?

I'm not asking about the situation when brolly is not on a list of preferred suppliers of particular agency.

It's rare but I've seen it.

Agent: "Have you got your own Ltd Co?"
LM: "Yes, why?"
Agent: "Good, ClientCo doesn't like contractors who work through umbrella cos"

That was a couple of years ago and I have no idea why client co felt that way. Didn't ask.

[LisaContractorUmbrella]

There is no reason at all why an agency would not work with an umbrella company other than preferred suppliers lists. They may refuse to work with companies who brand themselves as umbrella companies but are actually tax avoidance schemes or with companies who are based offshore as they are prevented from doing so by the offshore intermediaries legislation

[AutomationGuy]

As per title, was anyone declined a contract, because working under a brolly? Did anyone strictly insisted on working via LTD?

I'm not asking about the situation when brolly is not on a list of preferred suppliers of particular agency.