First, note the exact page address, error message, and when the problem started. Try a private browser window and, if possible, another device or network to see whether the issue is limited to one setup. Do not bypass certificate or security warnings.
Contact RJGA with your full name, business name, email, phone number, website, and a description of the issue. Include screenshots with private information removed, recent changes, and whether all visitors or only certain users are affected. Tell us the business impact. Avoid repeatedly changing DNS, deleting files, or restoring backups while the cause is being investigated.