There is a form for "Employee Contributions to a Foreign Pension Plan or Social Security Arrangement for 2017 – Non-Unite..." - Form RC269-17e. Check to see if your particular country qualifies.
You may want to contact CRA for further clarification and confirmation regarding your particulars. See form below.
Under "Income" from the left side menu --> choose T-slip --> Foreign Slip --> Fill the proper Boxes by indicating the country, type of income (there are different boxes for pensions from the United States or other), and you will find a box for Foreign Tax Paid.
Some pension income from some countries is subject to tax exemptions if the countries have entered into tax treaties with Canada. The list of the countries can be found in this link:
If you still have issues after following this process, please contact our support line:
I hope this was Helpful