SimSmsBox Quick answer: If Claude (Anthropic) signup blocks on phone verification, rent an overseas real-SIM number on SimSmsBox and receive the SMS code — same pattern as ChatGPT: nearby country, SMS only, prefer
physical. Service key is usuallyanthropicorclaudein the shop.
Like ChatGPT, Claude is sensitive to virtual numbers and abusive signups. When email works but phone fails, a clean overseas real-SIM SMS number is the most reliable fix.
Why Anthropic rejects numbers
- Broad VOIP / virtual ranges blocked;
- Free public pools burned out;
- Number country far from your IP;
- Voice call selected while rented numbers only get SMS.
Related troubleshooting: SMS code not received.
Verify Claude with SimSmsBox
Basics: how to use an SMS platform.
1. Finish email first
Stop at “Verify phone,” then buy a number.
2. Purchase real SIM
curl -X POST https://api.simsmsbox.com/api/sms/orders/purchase \
-H "X-API-Key: psk_xxx" -H "Content-Type: application/json" \
-d '{"service":"anthropic","country":"US","cardKind":"physical","rentDays":30}'
# Or search the shop for claudeWhy physical: real SIM vs virtual.
3. SMS only
Send the code via text, not call.
4. Poll
curl https://api.simsmsbox.com/api/sms/orders/81 -H "X-API-Key: psk_xxx"Cost & stock tips
| Item | Tip |
|---|---|
| Country | Match IP / region |
| Line | physical |
| Paid | Free pools rarely work for AI apps — paid SMS platforms |
| Failures | Cancel and reorder |
Boundaries
Receive-SMS is for signup verification; keep long-term recovery on email/2FA you control.
FAQ
Q: No anthropic in the shop?
Try claude or another alias; change country if out of stock.
Q: Same number for ChatGPT and Claude? Order per service; don’t assume one rental covers both forever.
Takeaway
Claude phone verification failing? Use a clean overseas real-SIM SMS number — nearby country, SMS only, poll the code. Platform comparison: SMS platform vs 5sim.