When the token expires, you can refresh your token through the following steps:

1- Request URL:

https://gateway.optt.ca/gateway/uaa/oauth/token

2- Request Method:
POST
*3- Input type: *
Query Parameter
A complete example of an API call:
**

https://gateway.optt.ca/gateway/uaa/oauth/token?refresh_token=${refreshToken}&grant_type=refresh_token

API Inputs:

Parameter Name	Parameter Type	Description
refresh_token	string	refresh_token
grant_type	string	Always put a refresh token

Sample response in JSON format:

{
"access_token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE2MDM2Njk1MDYsInVzZXJfbmFtZSI6Imluc3RpdHV0ZSIsImF1dGhvcml0aWVzIjpbIklOU1RJVFVURSJdLCJqdGkiOiI2NWJhNDFhNy05OThlLTQwZjEtYmUyYS1hMDI2YzYwZWQ3ZGQiLCJjbGllbnRfaWQiOiJvcHR0LTAyZWU3N2RjLWFjNDUtNDM0NC04MTdlLTE3Y2E1MmI1OGI1ZCIsInNjb3BlIjpbInJlYWQiLCJ3cml0ZSJdfQ.LteUnSohWZOQNs9yTLnASVDdT1w1oZ6rJJYjFmx69x32_wpb7E_d5bsB0OFsBOXXLgSC0KHR2_W9uvETxZXJ_EfEQPtyDn2zpWCLnzyeup4cfNCGw9mQymgbxNuxXAJjFpw1E1s1gs7uWLZOk5aGVOW9qhVYP7LyuVB-AQVFKydJVb0SM6nJoyKWA95N3bysR8rh-q_PWMUU7ZNLSuXUnOBe9BiG0IJK0iN-fohJQdnR8FhA2aEirbdmHvlL2NVx57QyE7Q3QX5_-0DsFWQxuUhqgEsl_Ef3zB2BZUCymugodb-fuhw1fBDO0S_dPdLShz3ghGy1PeL3rUZsWyw5Uw”,
"token_type": "bearer",
"refresh_token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX25hbWUiOiJpbnN0aXR1dGUiLCJzY29wZSI6WyJyZWFkIiwid3JpdGUiXSwiYXRpIjoiNjViYTQxYTctOTk4ZS00MGYxLWJlMmEtYTAyNmM2MGVkN2RkIiwiZXhwIjoxNjAzNjY5NTA2LCJhdXRob3JpdGllcyI6WyJJTlNUSVRVVEUiXSwianRpIjoiZjQxNjJkYTUtZDlhMC00NjRkLWE1YTctNjkwNzI1NGRiNjYwIiwiY2xpZW50X2lkIjoib3B0dC0wMmVlNzdkYy1hYzQ1LTQzNDQtODE3ZS0xN2NhNTJiNThiNWQifQ.L3RuCnCBf1WYV1u9ini9VkbASdrZ0kzWBY6s7ybrasWtE1FxdvXJcBW36BSQ4BHYDjU4vzYb8KS0JmV9FeCwVUL7nF2Q5ytlYm6jbVTlTmdBMo7Kbc4xxF4XOG_qOT_tEgPv3jLzlK0XUFq_bZONF4Z_yHqQWZ0oV1aqj4oHv9hEKfnmsRihSgN3QG0twnl52hGPzUoO64CLXmmvg3iSGnZU2Ancit9Lqj4UXiaQGd2DjESngUwokAFzB3SwaUaa9idgDd-CiDA_-TyVV5qtO8toBi4YCfht8_1efwoAqw4TQ7knEEoqAxLPV5s7FPBp_FhOR6pnhkFKEEZolEkDPg",
"expires_in": 35999,
"scope": "read write",
"jti": "65ba41a7-998e-40f1-be2a-a026c60ed7dd"
}

Important Point:

If the Refresh_token service responds with a 401 error code, it means that the token refresh has also expired, the user must be redirected to the login page and re-authenticated and receive a completely new token.