When I send a text, it only gives me an exclamation point with the Code (405) Method Not Allowed. Any ideas how I can enable the texting?
Chat requires SIP SIMPLE. This has to be supported by your server / provider. Also, messaging is a premium feature, not available for the free versions.
So I should contact Lightspeed? Also, what version includes the texting and is it a monthly fee or a one time fee?
Yes, you should contact your VoIP provider and ask them if they support the same method for messaging as Zoiper (SIP SIMPLE).
You would also need to purchase Zoiper Premium to use this feature. This will be a one-time purchase.
Alternatively: Xmpp Texting
for iOS [and android]: Chat Secure
Liberate yourself from legacy sms texting.