firewall blocking safe site

a couple of days ago a site i visit every day and know is totally safe, was blocked by my firewall. by process of elimination through various fix its, i discovered that stopping my firewall let me connect to the site fine. but when its turned back on i get a service is temporarily unavailable note on the site. it's the only site i can't get to. i talked to the site directly and they said it had to be on my end. i tried to manually allow the site through norton but it didn't work. i also tried to live chat this issue but they wanted to do remote access and i'm not comfortable with that. so hoping to find a solution here!

the site is www . tumblr . com

it's not a block through the internet, like when it says it's a malicious site or whatever either so i'm at a loss