At our school the wifi can be a bit frustrating at times. Depending on where you are, how many devices are connecting in the classroom and if there is a full moon or not.
Here are a couple of things to try that may help when your lesson goes SPC pear shaped with technology.
Check the wifi in your classroom. Ask the students to login to something like the Schoology app on their iPads. For some reason the app finds it more difficult to login if the wifi signal is low.
If you have no luck or students are waiting too long to login ask them to try logging in with the Safari app. Students can type in the URL of the site they are wanting to access.
Whatever they are trying to login to. This can sometimes be a bit quicker and work when the wifi signal is low.
If for some reason the class is still having problems logging into your class site you can ask just few students to try at a time. I usually ask no more than around 6 students to try logging in.
Ask your other students to put their iPads to sleep to save a bit of the bandwidth in your classroom.
If an individual student is having problems loggin in ask them to do a hard reset of their iPad. They can hold the sleep button on their iPad for around 8 seconds. This will then bring up a shut down option. Shut down and restart.