Hi,
I guess a few things to check would be:
- Mods
- Ping
- Integrity of files
I know you've stated you have all the correct mods, however people have gotten into the server with incorrect mods before and experienced such situations as you've described and realised they don't have the perfect list.
Secondly, if you try using your CMD and pinging the respective server, you might be able to ascertain if you are having a bad day for internet usage. Sometimes if your ping is too high, it can take over 5 mins to get into a server.
Thirdly, your files for whatever reason, including the Arma 3 game itself as well as the mods may have got a little bit jumbled with the recent updates of some mods, and such corrupted them, so try through steam to validate arma 3 as well as manually for each of the mods.
If you are still experiencing issues, I guess other members can offer further advice.
Respectfully,
LCpl Atom