Unable to read archived logs

Hello,

I'm having troubles searching into many archived logs: when I press "Load and search" they seem to load correctly, but then I press "Search" and, instead of the pop-up window containing the table and the search form, a blank pop-up window is opened.

I haven't been able to find any pattern that explains why some archived logs load properly and others don't. Also, I have manually opened the .zip files to rule out that the files are corrupted, and I am able to open and read the text files inside with no problems,

Can anybody give me a hint on why it happens and how can I get it to work? Thanks in advance