Outgoing calls do not work. Why can't I call?
There can be many causes of outgoing call faults. It is therefore important to narrow down the source of the error step by step.
If special numbers are called
If the fault occurs when dialling special or service numbers, please read "Why can't I reach special numbers?".
Does incoming telephony work?
First of all, please test whether incoming calls are working.
If not, please carry out the steps described in "I cannot be called, outgoing calls still work.".
Possible error when using your own sender number (CLIP)
Please check whether you have entered your SIP access data correctly in accordance with our instructions.
When setting up telephone systems manually, the so-called "From-User" field can often be adjusted separately in the advanced SIP settings. Your SIP user name must be entered in this field and not the desired sender number (CLIP). In this case, the call will be rejected by our system for security reasons.
Tip:
Make sure that only the SIP user name is used for authentication. The phone number may only appear as the sender ID (CLIP) in the call signal and not in the authentication area.
Further information on the SIP header structure and error analysis can be found in this article: SIP authentication: check SIP INVITE for outgoing calls
Is the device defective?
Test whether an alternative VoIP-capable end device, e.g. a softphone or a VoIP app, works.
If the problem persists after this, please send us a current call example with the key data from this help article.
