Error downloading as pdf a report with chart

Hello community,

A report without chart is downloaded as pdf correctly, but if I include some type of chart in the report, such as a bar, the system crashes with the following error:

Submitted URI too large!

The length of the requested URL exceeds the capacity limit for this server. The request cannot be processed.

I have increased the limit in the apache configuration and the error has already been removed:

LimitRequestLine 1000000
LimitRequestFieldSize 1000000

but the chart is not shown in the pdf report