If you have ever faced such downloading errors, then be sure that it's from your router. I'll try giving some tips in order to get it fixed, I hope this helps tho. First of all, try restarting your router, if that doesnt help, then try deleting all CIT resources that are listed in here, MTA > mods > deathmatch > resources (Delete all the exiting files in there that has CIT written in it).
If nothing of the mentioned solutions above work, try using a vpn, I remember I faced such an error before and i've fixed it throughout that way or connect an Ethernet cable from your modem to the wireless router (there is usually a short Ethernet cable included with your wireless router for this purpose).
@Natrig