Cannot telnet though could before

Although I was able to telnet before, I am no longer able to telnet. I am using Thief 1.25, which is a chess interface. The destination is freechess.org port 5000. Similar attempts to connect on port 23 have failed.

Why has it stopped working? Well, two things have changed. One is that I have switched antivirus programs to BitDefender. The second thing is that representatives from Claro (the phone company) came to my work and redid the Wifi network. The main change was the antenna, but some modifications were made to the configuration. Later another man, our standard computer guy came and refined those modifications.

Error received:
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

Things I have tried:
Connected to freechess.org from home. Site uptime exceeds 125 days.
Disabled BitTorrent on start-up to conserve bandwidth. No change.
Attempted to connect from another computer in the office. Failed.
Double checked windows firewall options. Outgoing permitted unless on a rules list. Should be okay.
Logged into access port (I have the admin password) and checked for possible anti-telnet configurations. Nothing noted.

Any advice would be appreciated.

P.S. Freechess.org (167.114.65.195) pings just fine.

Your answer was not helpful. Additionally, I doubt that you know what my work environment is like here in Peru.

Do you have access to a switch(ethernet port) directly? You could make sure it is the Wifi configuration if it would connect using Ethernet.

If not, it is also possible they changed firewall settings upstream.

I'll try that. It will have to wait till the weekend, though.