Since the image above doesn't show up, I include its content below:
{
"1": "The number of entities exceeds the limit.",
"3": "MUTATE_ERROR_ENTITY_COUNT_EXCEEDS_LIMIT",
"4": "criterion_id",
"6": 0,
"7": 0,
"9": "int64_value: 2004\n",
"13": "Each campaign is limited to 122 negative country criteria"