Some types of content and activity are illegal and are not permitted under any circumstances. The most obvious type of illegal content is pornography depicting children. Some lesser known tpes of content that are also illegal in Canada are pornography depicting bestiality or violence. It is also illegal to host some material for export (such as some kinds of encryption products) under export law restrictions.
It may be illegal in your jurisdiction to review the material to validate the report before removing the material. One must report the location of the material if it is available to the public through https://www.cybertip.ca/app/en/report. If you believe that your server was used to commit a child pornography offence you must preserve and archive any related material such as customer data, billing information and logs as evidence. This information should be reported to law enforcement immediately. The material retained as evidence must be destroyed after 21 days unless you are required to preserve the computer data by a judicial order made under any other Act of Parliament or the legislature of a province.
Other Types of Illegal Content
The solution to hosting most other types of illegal content is usually just deleting the content that is illegal. Please ask if you are unsure or contact legal counsel if necessary.