Even though Microsoft does still provide security updates for Internet Explorer, they do not update it with the latest web standards. This has lead to our development team spending a disproportionate amount of time making sure what we build complies with Internet Explorer's outdated standards, testing the system on this alternate web browser, and then investigating bugs that come up and only affect IE. It's a lot of additional work all for a small, and ever decreasing, amount of people who continue to (unwisely) use Internet Explorer.
You can use Microsoft Edge, Google Chrome, or Mozilla Firefox to access ResourceConnect.