email website no longer opens

my work e-mail has a webmail function (http://mail.hrwc.org/exchange). i was able to open the website (i.e. get to the login page) through last friday, but after the avast update saturday, i am no longer able to open the website - - all i get is a “connect” icon that keeps moving to indicate it is working, but the page never opens.

a colleague suggested that avast may be blocking the webmail webpage.

[note: i see that some other responses to questions ask about a “firewall”. how do i go about finding out what kind of firewall i have.]

how do i code that webpage (website?) as “safe”

many thanks to anyone who can help.

You can know your firewall by Control Panel > Security Central > Firewall
Probably it’s Windows one and it’s not a problem here.
Which is your browser? Internet Explorer? Firefox?