If you encounter a technical issue when trading, the first thing you need to do is remain calm and patient. Make a detailed note of the technical issue you encounter; this might help in the quick resolution of the issue.
Then, check if the trades you placed, if any, have been executed or not. If you need to place any trades urgently, you may contact the customer support helpline of your stock broker and request them to place the trade over the call.
If the technical issue is from the stock broker’s end, raise the issue with customer support. If the issue is from the stock exchange’s end, trades will generally be temporarily suspended until the problem is resolved.