Tried the aforementioned regex and was expecting it to filter for calls to international phone numbers

Question

In FusionPBX we want to create a regular expression that allows for calls to international phone numbers. However /+(\d{1,15})/g works on regexr.com, but not in fusionpbx. How can we modify the regex so that it works on fusionpbx?

We tried the standard regex and tested it, but it did not work out on fusionpbx.