HTML 500 Error only on file download attempt

Hi,
In my website there are some files available for download, but users are complaining that when they try to download a file they get a 500 HTML error code.
I’ve already changed the plugin I used to manage the files available for download, I’ve re-uploaded the files, but the error persists. And it only happens when someone tries to download a file, and not in any other situation. I’ve seen other posts and walk throughs on how to solve the 500 error but nothing seems to fix it, and I also contacted Godaddy, and they don’t seem to now what is going on.

When I try to download a file and get the error my PHP Log error registers the following:
PHP Fatal error: Call to undefined method APCu_Object_Cache::incr2() in /home/content/p3pnexwpnas04_data02/48/3270348/html/wp-content/object-cache.php on line 242

And I have no idea what to do.
Here is a link to a post on my website that has a link to download a file (it’s in Portuguese)
https://www.funcaoexcel.com.br/planilha-pronta-controle-uber/

Can someone help me?

Thanks in advance.