Grandstream ATA V2 issues

[sevenvoip]

I have probably 20 or so Grandstream ATA's (802 and 812's) in our field. All setup directly to a SIP provider for faxing. These have worked for 8-10 years now with no issues. I recently had power surges at one location and it fried the ATA's. I installed 3 new Grandstream ATA 812 V2's, and now faxes are VERY intermittent. Some go through and some don't. These ATA's are strictly for sending out faxes. Has anyone had similar trouble with these V2's?

 

[SweetAction]

Setup to a SIP provider or setup to 3CX (which uses a SIP provider).
Could you compare setting by setting a working on to a non working one?