Nine hundred people tested positive for coronavirus upon their return to the German state of Bavaria — but they don’t know it yet. Data entry problems mean thousands are still waiting for their covid_19 test results.

Bavarian State Premier Markus Söder was to meet with state government officials on Thursday after a serious breakdown of coronavirus test centers on state highways.

Söder has fielded criticism after Bavaria’s Health Minister Melanie Huml announced on Wednesday that 44,000 travelers returning to Germany’s largest state were still awaiting their COVID-19 test results, of which 900 are positive.

Following the announcement, Söder, who had to cancel a holiday to the North Sea coast, called the situation “very, very frustrating.”

“This must be fixed immediately and must not happen again,” he said in a tweet Wednesday. “All structures must be checked immediately.”

German Health Minister Jens Spahn came to Söder’s defense, saying during an appearance on public broadcaster ZDF that “mistakes happen in such extraordinary times.”

Huml said on Wednesday that a majority of the returning travelers awaiting COVID-19 results were tested in three coronavirus testing stations on Bavarian highways. She said the ministry had “no knowledge yet if any samples have been lost.”

Travelers have been able get tested at such centers since July 30 as Bavaria, which has had the highest rate of infection of any German state since the pandemic began, grapples with the virus. But according to the Munich-based Süddeutsche Zeitung, several travelers have complained that they have received the results of their test very late.