zoom freezes during share screen calls

HI All

So keen for some help! 

I have a client who sets up workshops in zoom, that I am a guest presenter on. They also sometimes make me the host.

The challenge:

About 45 minutes into every workshop, when I ma sharing my screen with a PowerPoint pack running the workshop, my camera starts to freeze, then my screen blacks out, then my whole computer starts to freeze and close me out of the workshop. 

I have already tried:

- Contacting my IT support and they say this is not a computer hardware issue

-Have checked internet and this doesn't seem to be the issue

It does not happen on other software (MS Teams etc)

Has anyone had this issue and do they know how to resolve?

Thanks

Holly