Wisconsin wireless provider Cellcom has confirmed that a cyberattack is responsible for the widespread service outage and disruptions that began on the evening of May 14, 2025.

The incident disrupted voice and SMS services for customers across Wisconsin and Upper Michigan, leaving subscribers unable to make phone calls or send text messages.

Today, after days of just calling it a technical outage, Cellcom CEO Brighid Riordan has confirmed what was already suspected: that the company suffered a cyberattack.

“We experienced a cyber incident. While this is unfortunate, it’s not something we were unprepared for,” reads a letter from Cellcom CEO Brighid Riordan.

“We have protocols and plans in place for exactly this kind of situation. From the start, we’ve followed those plans — including engaging outside cybersecurity experts, notifying the FBI and Wisconsin officials, and working around the clock to bring systems safely back online.”

“The incident was concentrated on an area of our network separate from where we store sensitive information related to you, our Cellcom/ Nsight family. We have no evidence that personal information related to you, your name, your addresses, your financial information, is impacted by this event.”

Cellcom initially claimed the disruption was caused by a technical issue, stating that data services, iMessage, RCS messaging, and 911 emergency services remained operational.

However, users became increasingly frustrated with the loss of service and the inability to port their numbers to other carriers due to Cellcom’s platforms having issues.

On May 19, Cellcom began bringing some of its services back online, including SMS text messaging and making and receiving phone calls to other Cellcom subscribers.

However, the company says that while they can’t promise when services will be restored, they are trying to restore full service by the end of the week.

“While we would like to provide a timeline for full restoration, we are unable to share exact milestones with complete confidence. Our team continues to build on the progress shared yesterday and our best estimate is that full service will be restored by or before the end of this week,” reads a service updates page on Cellcom’s site.

For Cellcom subscribers having issues recovering services, it is recommended that they enable airplane mode for 10 seconds and then disable it again. If that does not work, subscribers should power down their phones and start them up again to attempt to initiate services.

Yesterday, BleepingComputer contacted Cellcom with questions about the disruption caused by a ransomware attack or another cyber incident, but did not receive replies to our questions.

Cellcom CEO Brighid Riordan also shared a video for subscribers to explain the situation and what they are doing to recover from services.

The total land area in OpenSim fell this month by over 3,000 standard region equivalents, the total number of registered users fell by just over 1,000, and the number of active monthly users dropped by 425 compared to this time last month.

The region loss was due to the fact that Discovery Grid did not report its region totals this month. In April, the grid reported 5,178 standard region equivalents.

In addition, several grids did not report their stats this month, including Kater and Friends, ProxyNet, Caribou Grid, and Resurgence. Each of these grids has reported hundreds of active users earlier this year. If the grid has moved, please let me know at maria@hypergridbusiness.com.

The numerical losses were not due to 3rd Rock Grid’s closure yesterday, since that grid still showed up as active for the past four weeks and did report its stats. Its loss will show up in next month’s stats report.

The total land area on OpenSim’s public grids reached the equivalent of 135,700 standard regions this month, down from last month’s all-time high — and still several times bigger that the total land area of Second Life.

The biggest gainer in terms of land area was OSgrid, which gained 1,160 new standard region equivalents, maintaining its status as the largest public grid in OpenSim. It was followed in growth numbers by ZetaWorlds with 1,024 new regions and Wolf Territories Grid with 384 new regions.

At the same time, the number of active users dropped to 47,195.

Wolf Territories Grid retained their first-place position by traffic numbers.

I’m now tracking a total of 2,661 OpenSim grids, of which 307 were active, and 249 published their statistics this month. If you have a stats page that we’re not tracking, please email me at maria@hypergridbusiness.com — that way, your grid will be mentioned in this report every month, for additional visibility with both search engines and users.

The following grids were added to our database this month: 3World, BachmansWorld One, Bridger, CyberDataStorm, and Dark Heaven.

Also, I’m no longer sending out a monthly email blast reminding OpenSim grid owners to send me news and updates for this report. If you have news, please email me before the tenth of the month if you want a short item included in this monthly wrap-up. For longer news, feel free to send me press releases at any time.

Our stats do not include many of the grids running on DreamGrid which is a distribution of OpenSim since these tend to be private grids.

OpenSim is a free open-source, virtual world platform, that’s similar to Second Life and allows people with no technical skills to quickly and cheaply create virtual worlds and teleport to other virtual worlds. Those with technical skills can run OpenSim worlds on their servers for free using either DreamGrid, the official OpenSim installer for those who are more technically inclined, or any other distribution, while commercial hosting starts at less than $5 a region.

A list of OpenSim hosting providers is here. Download the recommended Firestorm viewer here and find out where to get content for your OpenSim world or region here.

Hypergrid Business newsletter is now available

Every month on the 15th — right after the stats report comes out — we will be sending out a newsletter with all the OpenSim news from the previous month. You can subscribe here or fill out the form below.

Top 25 grids by active users

When it comes to general-purpose social grids, especially closed grids, the rule of thumb is the busier the better. People looking to make new friends look for grids that already have the most users. Merchants looking to sell content will go to the grids with the most potential customers. Event organizers looking for the biggest audience — you get the idea.

Top 25 most popular grids this month:

1. Wolf Territories Grid: 5,904 active users
2. OSgrid: 5,263 active users
3. GBG World: 2,174 active users
4. DigiWorldz: 2,125 active users
5. Alternate Metaverse: 2,001 active users
6. Darkheart’s Playground: 1,462 active users
7. WaterSplash: 1,419 active users
8. Vida Dupla: 1,222 active users
9. Moonrose: 1,149 active users
10. AviWorlds: 1,105 active users
11. Neverworld: 1,086 active users
12. Trianon World: 1,014 active users
13. Littlefield: 993 active users
14. Craft World: 965 active users
15. AvatarLife: 940 active users
16. Party Destination Grid: 845 active users
17. Astralia: 773 active users
18. Virtualife: 750 active users
19. Kitely: 655 active users
20. German World Grid: 623 active users
21. ZetaWorlds: 618 active users
22. Herederos Grid: 588 active users
23. CandM World: 563 active users
24. Groovy Verse: 505 active users
25. Eureka World: 490 active users

Top 40 grids by land area

All region counts on this list are, whenever available, in terms of standard region equivalents. Active user counts include hypergrid visitors whenever possible.

Many school, company, or personal grids do not publish their numbers.

The raw data for this month’s report is here. A list of all active grids is here. And here is a list of all the hypergrid-enabled grids and their hypergrid addresses, sorted by popularity. This is very useful if you are creating a hyperport.

You can see all the historical OpenSim statistics here, including polls and surveys, dating all the way back to 2009.

• OSgrid: 30,960 regions
• Wolf Territories Grid: 28,928 regions
• Kitely: 18,085 regions
• ZetaWorlds: 12,772 regions
• Alternate Metaverse: 9,811 regions
• Groovy Verse: 7,864 regions
• DigiWorldz: 3,546 regions
• German World Grid: 2,476 regions
• CandM World: 1,760 regions
• Tag Grid: 1,464 regions
• Shoalwater Bay: 1,072 regions
• GBG World: 956 regions
• Virtual Worlds Grid: 915 regions
• 3rd Rock Grid: 872 regions
• AviWorlds: 853 regions
• Friends Grid: 816 regions
• ArtDestiny: 784 regions
• Kinky Haven: 669 regions
• AvatarLife: 605 regions
• Littlefield: 514 regions
• Craft World: 471 regions
• GorGrid: 430 regions
• Tomi’s World: 400 regions
• Furry World: 373 regions
• Neverworld: 344 regions
• DreamNation: 318 regions
• Nemesis 3D: 305 regions
• EdMondo: 300 regions
• Open Virtual Worlds: 241 regions
• Japan Open Grid: 194 regions
• Counter Earth: 186 regions
• MisFitz Grid: 181 regions
• Adreans-World: 173 regions
• GerGrid: 141 regions
• OpenSim Fest: 140 regions
• Darkheart’s Playground: 137 regions
• WestWorld Grid: 135 regions
• Outworldz: 127 regions
• Galactic Virtual: 127 regions
• Logicamp: 123 regions

Do you know of any other grids that are open to the public but that we don’t have in our database? Email me at maria@hypergridbusiness.com.

Hypergrid Business editor and publisher Maria Korolov is a science fiction novelist. During the day, Maria Korolov is an award-winning freelance technology journalist who covers artificial intelligence, cybersecurity and enterprise virtual reality. See her Amazon author page here and follow her on Twitter, Facebook, or LinkedIn, and check out her latest videos on the Maria Korolov YouTube channel. Email her at maria@hypergridbusiness.com. Her first virtual world novella, Krim Times, made the Amazon best-seller list in its category. Her second novella, The Lost King of Krim, is out now. She is also the publisher of MetaStellar, a new online magazine of speculative fiction.

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