If you have any problems with Comodo with any sites and attempt to get support the site operator will just tell you to use a mainstream browser. There is a reason for this.

To be perfectly honest, I am not sure what Comodo gives you that Firefox won't - both are privacy focused browsers however Firefox is mainstream. Seriously, you should just switch to that. There is also the new Microsoft Edge which is a bit better in terms of privacy than Google Chrome if you wanted a chromium browser also.