A marijuana point-of-sale software platform company was shut down by hackers over the weekend, effecting up to 1,000 marijuana dispensaries across 23 states that use the software, the company announced.

MJ Freeway, a software company based in Denver that helps dispensaries track inventory, process sales and stay compliant with state marijuana laws, announced on Twitter that hackers brought down its main servers and backup system on Sunday. The system was still down on Tuesday.

According to Marijuana Business Daily, which first reported the outage, the attack hit the company's infrastructure, bringing down its main database and backup databases, but client data was not stolen. MJ Freeway does not know who attacked the company.

MJ Freeway assured clients that personal information from medical marijuana patients and recreational users is safe.

"The data was encrypted, so patient information is still protected. We are prioritizing security first to protect you and your clients," MJ Freeway said in a Tweet. "We want clients to know that all client data is locked behind firewalls."

Most banks, credit card companies like Visa, Master Card and POS companies will not serve the federally illegal cannabis industry. But companies like MJ Freeway, BioTrack THC and Flowhub have stepped up to provide the desperately needed service. Most states have implemented laws that require dispensaries to use "seed-to-sale" tracking software to track product from the plant, to the shelf, and finally to the customer. The system is meant to prevent marijuana being diverted into the black market. This means if a dispensary's seed-to-sale software is down, the risks are high--a dispensary can lose its license to sell marijuana if product goes missing or is unaccounted for by the end of each day.

The outage effected approximately 1,000 retailers that rely on the platform to process sales and ensure compliance, resulting in dispensaries closing or doing each transaction by hand.

According to Marijuana Business Daily, dispensaries using the software in Colorado, Arizona and Nevada were either closed or doing manual transactions, resulting in long lines. The Boston Globe reported multiple dispensaries in Massachusetts had to close while the POS platform was down.

Herbal Alternatives, based in Washington, D.C., told its patients via Twitter that it will stay open through the outage.

"Our Point of Sale @mjfreeway is down NATIONWIDE! We have to do everything manually. Expect a long wait, but we'll still make it happen!"

By press time on Tuesday, MJ Freeway's website was still down.