> For the complete documentation index, see [llms.txt](https://docs.blynk.io/en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.blynk.io/en/getting-started/what-do-i-need-to-blynk/troubleshooting.md). # Troubleshooting ## I C**an’t Sign Up or Log In** Check that correct hardware and port are used when uploading the sketch **Potential Reasons:** * Wrong email address * The password is incorrect * The user with the specified email address is not registered in the system Check that your device connects to 2.4 WiFi network **Solution:** * Specify correct email address * Be sure to type the correct password * Reset password * Check the specified email inbox to be sure it's registered in the system * Register with a different email address ## **No Email Received** **Potential Reasons:** * You entered an incorrect email address * The email got into the SPAM folder * Email server issues **Solution:** * Specify correct email address * Check your SPAM folder * Contact you mail server administrator ## **No Connection to Cloud Server** **Potential Reasons:** * You do not have an Internet connection * The server is rebooting * Intermediate providers issues **Solution:** * Check your Internet connection * You should wait for a while to reboot the server * Run traceroute command in your OS terminal, contact your ISP and provide them with this data ## Device is Offline **Potential Reasons:** * Connectivity issues * Incorrect SSID or password in the sketch code * SSID or password are not specified in the sketch code * Old version of library or even beta version is used * Outdated ESP core version **Solution:** * Check if the device is powered on * Check your Internet connection between the device and Blynk.Cloud (mind Wi-Fi signal strength and distance) * Be sure to use the latest version of library, otherwise re-flash and launch Device Reprovision process * Check your ESP core version is up to date, otherwise re-flash and launch Device Reprovision process Checked all of the above and are still unsure what’s going wrong? Contact our technical support team for prompt help (available with [PRO plan](https://blynk.io/pricing)). --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.blynk.io/en/getting-started/what-do-i-need-to-blynk/troubleshooting.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.