Nick bryner, a high school senior in Los Angeles, spent hours completing his AP English literature and composition test last week. When he snapped a photo of a written answer with his iPhone and attempted to upload it to the testing portal, it stopped responding.

The website got stuck on the loading screen until bryner’s time ran out. He’s retaking it in a few weeks.

Many high school students around the country completed advanced placement tests online last week but were unable to submit them at the end of the end. The culprit: bryner is among the many students who completed advancedgnancies online.

Students can either type their response or upload a photo of handwritten work. College Board: students who choose the latter option can do so as a JPG, JPEG, or PNG.

The testing portal does n’t support the default format on iOS devices and some newer Android phones, HEIC files. Heic files are smaller than JPEGs and other formats, so allowing you to store a lot more photos on an iPhone.

The issue was so common that his school’s AP program forwarded an email from the College Board to students on Sunday. Students also tried to submit iPhone photos and experienced the same problem.

‘what’s devastating is that thousands of students now have an additional three weeks of stressful studying for retakes,’ says bryner.

The College Board said that’the vast majority of students successfully completed their exams’ in the first few days of online testing. The company also noted that’we share the deep disappointment of students who were unable to submit their responses’.

The College Board’s website instructs students with iPhones to change their camera settings so that photos save as JPEGs rather than heics. The company also linked to that information in a Tweet early last week.

If you want to submit a photo of a handwritten AP exam exam answer from an iPhone or iPad, make sure to change your settings so your photos are saved as JPEGs, not heics.

One senior said that the College Board’s Tweet went out just a few minutes before his test began. He said that no one taking the AP physics test would have been able to see it.

Senior Dave Spencer airdropped an iPhone image of his responses to his Mac and tried to convert it by renaming the HEIC file to PNG. Changing a file’s extension does not guarantee that it will be converted, but Spencer was still able to submit the demo test with no problem.

The College Board’s Tweet went out just hours before Spencer’s scheduled exam. He did n’t have a Twitter account and did n’t see it.

‘this is absolutely unacceptable, as some kids may not have Twitter like me,’ says Spencer.’that Nuance was not addressed anywhere in the demo’.

Everly Kai, a senior in British Columbia, had the same problem with computer science last week. She attempted to rename the file to JPEG and received the same email hours after submitting her test test test.

‘it was honestly a bit devastating,’ says Kai. I’d have to go through the entire stressful process again,’ he said.

bryner does n’t think the company should have expected him and his classmates to jump through so many hoops.’to flip the switch from HEIC to JPEG is buried in settings, and something that no one is thinking about going into the test,’ he said.

Sean S. a junior from Chicago, used OneDrive to port a photo to his Windows desktop from his iPhone. Due to the photo’s size, the conversion took over five minutes. Before the JPEG had fully submitted, his time ran out.

The College Board is now allowing test-takers who have issues submitting their tests to email them instead. Iphones convert heics to JPEGs automatically when they’re attached to emails in the mail app.

Los Angeles senior eliana sisman created a petition to allow her and fellow students to resubmit their previous tests. The petition has collected over 23,000 signatures.

The College Board set up a re-submission channel for students taking APS this year.’many students will be in the military or working at summer jobs by June 1st and wo n’t be able to take the makeup test,’ sisman said.