Whatsapp OCCASIONALLY not working at my office Wi-Fi?

So i have this weird issue at the moment where my Office WiFi at work is not letting me send or receive messages sometimes. One day it'll be perfectly fine all day, no issues, but then other days i'll send a message or two between 9am-11am and it works fine, but then ill try again around midday and it just gets stuck at sending with the grey clock there.

But i can occasionally get a message through sent to me but it just wont send them to anybody else.

I also can no longer send photo's at all.

This is only my Whatsapp, my colleague who has an iphone isn't effected by it, and it rarely happens to my other colleague aswell who has a Samsung.

I have a Samsung aswell. So i thought it could be a samsung fault. Is there anything that can be done about this? Tried contacting Whatsapp but no reply.
Im stuck for answers…

Also i can't use Snapchat at work either.

Its like my apps are getting blocked but only at random times and work hasn't blocked anything.
Added (1). Also forgot to mention that when it gets stuck on the grey clock, it won't send a message at until until i have finished work and connected to my home Wi-Fi or use my data plan.

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