When Sonoff is offline, the LEDs generally remain lit:

Red = power

Blue = WiFi

the third and last LED is off.

On the phone appears:

It is likely that the router has received an irregular signal and does not recognize the Sonoff.

Quick solution that works 95%.

Turn off the general power (router and Sonoff) for 10 seconds.

When turned back on, the router checks all connected devices and restores the connection.

The "950" prefix in the EAN code is a special code assigned to the GS1 Global Office. Unlike other EAN prefixes that are generally assigned to specific countries or regions, "950" is used for global purposes and is not tied to a geographic location. This prefix is used for products or services that require unique identification at an international level and do not fall under standard national or regional categories.

For example, GS1 might use this prefix for barcodes that are intended for international programs, special initiatives, or for products that cross multiple borders and require coding that is universally recognized. Additionally, the "950" prefix can be employed in situations where a product needs an identification that transcends national conventions, such as in the case of certain digital products or online services.

In the EAN code system, the initial numbers "981" and "982" are used for special purposes and are not assigned to specific countries as is the case with most other EAN prefixes. 

These prefixes are reserved for use in coupons and discount vouchers. Specifically, EAN codes starting with "981" and "982" are intended to identify global coupons. 

This allows retailers and manufacturers to create barcodes that can be recognized and processed internationally for promotional offers, discounts, and coupons.

The ISSN 979 code, similar to 978, is used in the context of the ISBN (International Standard Book Number), but it does not refer to the ISSN. 

The 979 prefix was introduced to expand the capacity of the ISBN system in response to the increasing number of publications. 

While the 978 prefix is used for books and non-periodical publications, the 979 prefix was initially reserved for printed music (such as scores), but it has since been extended to include books as well. This expansion ensures that there are enough ISBN numbers available to meet the growing global demand for publications.

The ISSN 978 code is used to identify books and other non-periodical publications. 

Actually, the "978" prefix is associated with the ISBN (International Standard Book Number), not the ISSN. 

The ISBN is a unique identifier for books, assigned to each edition and variation (except for reprints) of a book. The ISBN system aids in the identification and cataloging of books by publishers, libraries, book retailers, and distributors. The transition to the 13-digit ISBN format has allowed integration with the EAN system, making it easier to sell and distribute books globally.

The ISSN 977 code is specifically used to identify serial and periodical publications such as magazines, newspapers, and electronic journals. "ISSN" stands for "International Standard Serial Number", a unique eight-digit code that assists in the identification and tracking of such publications internationally. 

The "977" part of the code is a standard prefix for EAN barcodes representing serial publications. 

This system aids in managing publications in libraries, distribution systems, and databases, ensuring an efficient and standardized way to refer to specific serial publications.

GS1 barcode labels are a12-digit standardized system for encoding information about products and services. 

These barcodes are used globally across various industries, including retail, healthcare, and transportation. 

The most common types are EAN/UPC barcodes, primarily used on consumer goods. GS1 logistic labels enable the tracking of logistic units in the supply chain. GS1 also offers services to verify and ensure the uniqueness of barcode numbers. 

Businesses must follow specific guidelines for printing and placing barcodes on products, ensuring their readability and compliance with international standards.

GS1 Barcodes - Standards. Barcodes are symbols that can be scanned by proper systems and play a key role in supply chains. Find here several types of barcodes managed by GS1. 

GS1 Logistic Label Guideline. The GS1 Logistic Label allows users to uniquely identify logistic units so that they can be tracked and traced throughout the supply chain.