MyBB Community Forums

Hello there

My forum is 1.8.6 and was running on php 5.6. recently I tried to update the php version to 7.3 but many plugins like inline ads and Google seo giving errors. So I rolled back to php 7.1 and the forum is working fine. Later I noticed the member registration fails as after' clicking the agree button in the terms page and the forum throws an error 500 blank page. If I disable all captcha verifications it again works fine. What may be the error? Please help me to solve the problem..

Thanks in advance

1.8.6 won't work on PHP 7.3. MyBB 1.8.6 was released 6 years ago, PHP 7.3 was released less than 3 years ago, so 1.8.6 isn't compatible with 7.3 as it didn't even exist at the time. You need to update your forum urgently as you are 6 years behind on security fixes, and then you'll be able to run on PHP 7.4.