The availability of a web domain does not necessarily prevent you from registering a trademark in the US or Canada. Trademark registration and domain name availability are separate considerations, governed by different legal frameworks.
When registering a trademark, the primary focus is on the distinctiveness and potential for confusion with existing marks in the relevant industry. The fact that a web domain is already taken does not automatically disqualify your trademark application. However, if the existing domain is being used in a way that could infringe upon your trademark rights or create confusion among consumers, it may become a relevant factor in the registration process.
It's worth noting that the use of a domain name by a third party may create complications and potentially result in disputes, depending on the circumstances. If you believe the existing domain infringes upon your trademark rights or causes confusion, you may consider consulting with a trademark attorney to explore your options. This could involve negotiating with the domain owner, pursuing legal action, or utilizing domain name dispute resolution mechanisms provided by domain registrars.