Tesla has been forced to halt a project that would have seen it launch four new Supercharger projects throughout California due to a loss of public funding. The company’s no-screen design means that its charging stations aren’t eligible for millions in Clean Energy Commission subsidies.

The project would have seen Tesla add a total of 420 stalls throughout California creating the world’s largest Supercharger site, with a total of 164 charging points. The automaker was expecting to receive $1.6 million in public funding per project, for a total of $6.4 million from the state.

Unfortunately, the automaker has now informed state officials that it cannot accept the funding. In a letter seen by Drive Tesla, the company’s Policy and Business Development Lead, Jennifer Cohen, blamed the California Clean Energy Commission’s payment requirements for the decision.

Read: Tesla Is Already Adding Magic Dock For All Other EVs To Its Charging Network

 Tesla Rejects $6.4M Supercharger Public Funding Over Payment Constraints From No-Screen Design

“The California Clean Energy Commission (CEC) has been a great visionary in the expansion of electric vehicle (EV) charging infrastructure in California,” Cohen wrote. “Unfortunately, due to unnecessarily cumbersome payment infrastructure requirements, we are unable to utilize this award.”

More specifically, the state requires that chargers for electric vehicles have “multiple point-of-sale methods.” That is intended to allow drivers to pay by credit, debit, and through mobile apps. Tesla’s charging points, though, have no screens to facilitate the initiation of payments like these.

Presumably, developing a new charger with a screen would cost more than the automaker would receive from the CEC. One way or another, the automaker has decided to walk away from the funds. The simplicity of Tesla charging, meanwhile, has been cited as one of its advantages over other networks, most of which offer screens and have faced complaints of being overly complicated and prone to failure.

 Tesla Rejects $6.4M Supercharger Public Funding Over Payment Constraints From No-Screen Design
An Electrify America charging station

California’s state requirements are different from the federal government‘s, meaning that although non-Tesla chargers tend to have screens, the ability to charge vehicles other than Tesla’s wasn’t the issue here.

Earlier this year, the automaker started introducing adapters to its chargers that allow EVs from other automakers to charge at its Superchargers. That decision followed the federal government’s threat to refuse infrastructure subsidies to the automaker if it didn’t open its charging network to other vehicles.

It’s unclear at this time if Tesla’s inability to use the California CEC grants for the four above-mentioned projects means that they have been canceled, or simply put on hold. The new Superchargers were supposed to be located in Baker, Willows, Barstow, and Coalinga.

 Tesla Rejects $6.4M Supercharger Public Funding Over Payment Constraints From No-Screen Design