default upload size 1500kb

Please can someone help I’ve ran into this issue this is what my hosting company has said

Hey! Apologies for late reply.
While checking this, looks like Multisite has a default upload size 1500kb
This could explain why trying to increase the limit with script does not help.
Now while reviewing all your previous chats with my colleagues, I see that everything from our side was already suggested. If that does not help, I would recommend try to forward the issue to WordPress support or WordPress forums where developers would be able to help you with the issue directly. What do you think, would you like to try this?

The page I need help with: [log in to see the link]