On social media, Starbucks customers have reported not being able to order drinks like a mocha, Peach Green Tea Lemonade, and drinks using oat milk for weeks. Others claim that their local Starbucks is also often out of various syrups, making many drinks unavailable.

One TikTok user shared a video of a board outside a Starbucks drive-thru that listed the ingredients they were out of, including hazelnut, chai, matcha, and drinks trays. So, coffee fans may be wondering: why is Starbucks out of seemingly everything?

Starbucks has responded this week to concerned customers on Twitter by letting them know that its coffee shops across the country are experiencing supply issues.

Starbucks explained that “some stores are experiencing outages due to the overwhelming popularity [of] menu items, and constraints in the supply chain,” but said that it is, “working quickly and closely with our supply chain vendors to restock items as soon as possible.”

To a concerned customer who thought their favorite drink was being removed from the menu, Starbucks said: “We don’t plan on saying goodbye to the Peach Green Tea Lemonade! It will be temporarily unavailable as we work to restock some of your other favorite beverages.”

Starbucks told another disappointed customer: “We are experiencing nationwide outages and apologize if we don’t have your favorites in stock right now. We look forward to having Very Berry Hibiscus Starbucks Refreshers back on the menu again in the future.”

One customer asked when oat milk will be available to order on the Starbucks app, and the coffee chain said it will be available once they are able to restock the plant-based milk at Starbucks stores.

Starbucks also told customers it recommends “calling your local store or asking about availability when you place your order.”

Business Insider reported that Starbucks was facing shortages of products and ingredients including cups, flavored syrups, and baked goods, in early April. The coffee shop chain was experiencing oat milk shortages, in particular, a month after it launched the vegan-friendly milk alternative.

At the time, a barista at a Starbucks in Alabama told Insider that some days the store just doesn’t “get any shipments, and we’re operating on the bare minimum.”

In April, Starbucks CEO Kevin Johnson said: “In some areas in [the] supply chain, let’s take in distribution where store deliveries. Now some of our partners who run the store deliveries are from our customer distribution centers to stores, they’ve struggled a bit having—being able to hire and staff to meet the demand that we have and to get enough people.

“So we are working with them. So I do anticipate we’ll do a little bit more to invest and help our supply chain partners, whether it’s staff that they need in manufacturing or staffing they need for distribution and transportation. But when it comes to Starbucks, I think we’re in a very solid position.”

Newsweek has contacted Starbucks for comment.