PHP Fatal error: Call to undefined function adrotate_get_remote_ip()

Good morning,
I enabled the Click Tracking function and I see this error on Chrome:

GET http://[host]/wp-content/plugins/adrotate/library/clicktracker.php?track=MSw4LDAsMA== 500 (Internal Server Error)

On the Apache error log I found:

PHP Fatal error: Call to undefined function adrotate_get_remote_ip()

How can I resolve this issue?

Please help me.

I’m italian, sorry my bad english.

Best regards,
Andrea.

https://wordpress.org/plugins/adrotate/

[Duplicate: https://wordpress.org/support/topic/php-fatal-error-call-to-undefined-function-adrotate_get_remote_ip?replies=1%5D