Forced to use 3CX SMTP on registered annual licensed system

[bigohio]

What am I missing here?

I went to check on the SMTP configuration the server drop-down menu is grayed out and I can't change any settings. This is not the freeware edition.

 

[Saqqara]

You are running Std Edition - with V15.5 SP3 you have to use 3CX smtp server

https://www.3cx.com/ordering/pricing/

 

[YiannisH_3CX]

Regarding the error you are getting, this is probably caused because the IP you are sending the request in does not match the IP the last activation happened.
Please navigate to Settings / Network and set the option to "Dynamic Public IP" under the "External IP Configuration" . Then restart the 3CX services. Wait a few minutes and try again.