Hello Maria,
In ICM configuration, please check the value of the parameter icm/HTTP/max_request_size_KB. By default, it is 102400 - meaning that ICM will process HTTP requests of size up to 100 MB and will prevent processing larger requests. You can increase value of this parameter to a higher value depending on the size of HTTP requests that you expect to be passed to ICM. In extreme case, this limitation can be even switched off by setting value of the mentioned parameter to -1, but please take into consideration that switching off the request size limitation is not recommended from security perspective - since potentially very large requests may be sent to ICM and cause performance degradation / Denial of Service for ICM when being processed.
Regards,
Vadim