Beta tests are where companies help work out kinks on latest software updates before these get rolled out to all its users. It seems the latest version of Open Beta update for OnePlus devices has been causing bigger problems than usual, prompting the company to pull all versions from its site. The versions pulled include Open Beta 5 for the OnePlus 5T, Open Beta 7 for the OnePlus 5, Open Beta 24 for the OnePlus 3T, Open Beta 33 for the OnePlus 3. The main issue is said to be excessive battery drain, among other reported problems. Those who got the latest builds might have to wait a bit to get their phones fixed. There is no word yet from OnePlus when updates are coming.
Source: Android Police
We just got word from OnePlus that the builds for the phones were not intentionally pulled. According to a representative from the company, the links were removed because they're currently migrating from oneplus.net to oneplus.com. For those waiting for the Open Beta links to come back up, these will be restored soon.