Fatal error class-lp-user-factory.php

Hi,

I would need your help about an php issue. I tried to install Learnpress in my wordpress and I had the follwong error message after installation:

Fatal error: Call to undefined function get_userdata() in /home/vsftpd/test-dev_habb/test-dev_habb/wp-content/plugins/learnpress/inc/user/class-lp-user-factory.php on line 151

Could you please explain the way to resolve this issue?

Thanks a mil,

Florent