woocommerce shipping plugin

Hi.
I am facing integration problem between woocommerce and shipping plugin.
I installed purolator shipping plugin(https://woocommerce.com/products/purolator-shipping-method/?_ga=2.64292200.674121657.1601903708-1850588802.1595525802&_gac=1.54317146.1599051374.Cj0KCQjwhb36BRCfARIsAKcXh6GY1Mzw2xJnjvZwpF6TM7zJ06c_-ptN2oEqfV-aHUUK5Q8oH2BibRoaAth5EALw_wcB) to get real-time rate on checkout page. However, it did not show real-time rate and to make matters worse, once I activated the plugin, I could not proceed to cart page and showed errors by saying “there are critical error on your website. Learn more about debugging in wordpress”. I contacted support team of purolator plugin and they told me several suggestions but none of them did work. After that, I found easyship (https://www.easyship.com/), which provides us real-time rate and other many features related to shipping. But it also did not work at the stage of integration. Again, I contacted the support team and they said their system did not have problem.
I checked support forums whether the same issue was posted and most of them said it might happen due to the conflict of plugins. If so, how can I detect the one who is affecting the shipping plugin? Does anyone know other possible reasons this may occour?

Thank you for your help in advance!