These articles are organized by what you are seeing rather than by feature, because that is how problems arrive. Each one starts from a symptom, works through the likely causes in order, and links into the reference articles for the fix.
Whatever the symptom, start in the same place: open the SIM in the dashboard and run Diagnostics. It checks provisioning, network status and hardware band compatibility automatically, and it will often name the cause before you read any further.
What's in here
Connectivity issues, a SIM that won't connect at all, or registers without passing data. Covers SIM state, balance, coverage plan, data roaming, the APN for your profile, band compatibility and incidents
SMS not sending or receiving, what each SIM profile can actually do with SMS, and how to troubleshoot messages to the SIM separately from messages sent by it
Slow connection or high latency, a SIM that works but performs badly, including breakout location and what Simbase can and cannot influence
Public IP isn't reachable, a SIM with a public IP that won't answer inbound traffic, including device firewalls and the fixed IP APN for your profile
SIM disabled unexpectedly, why a SIM turned itself off, and what to check before re-enabling it
Start here
| What you're seeing | Go to |
|---|---|
The SIM shows offline and has never worked | |
The SIM registers but no data passes | |
A device that worked has stopped, but nothing changed | |
Messages to or from the SIM aren't arriving | |
The connection works but is slow, or latency is high | |
You can't reach the device on its public IP | |
Several SIMs stopped working at the same time |
The SIM shows offline and has never worked
The SIM registers but no data passes
A device that worked has stopped, but nothing changed
Messages to or from the SIM aren't arriving
The connection works but is slow, or latency is high
You can't reach the device on its public IP
Several SIMs stopped working at the same time
Before you troubleshoot
Two checks resolve a large share of reports and take seconds:
Is the account balance positive? A zero balance disables every SIM on the account. See Account balance and invoices
Is there an open incident? Check simbasestatus.com before investigating a device, particularly if more than one SIM is affected
Looking for something else?
Setting up a specific router or device → Device configuration
Designing connection logic and retry behavior for your own hardware → Optimizing device configuration
Checking a device supports the right bands before you deploy → Compatibility check
What the APN does and which one your profile uses → Set up the APN
Understanding a bill or unexpected usage → Data usage and overages
Reaching a person → Contact support
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