DavidGEP

Hello everyone, I am pretty new to here and on port forwarding, and to add to the mess im using a DLINK router that has had a known DDNS issue (so im not using ddns). My service provider Optimum Online and we only have the basic service. I found out that port 80, was blocked by Optimum so I have alternatively used port 81. So I have forwarded 3 ports. port 81, to my DVR internal IP port 37777, to my DVR internal IP (TCP) port 37778, to my DVR internal IP (UDP) i use my internal address, 192.168.0.XXX:81 to connect to my DVR with no problem. I cannot connect through an external address. My Phone app keeps giving me login failed. another thing to note is that whenever i use canyouseeme.org to check my open ports. 81 and 37777 are successfully opened, but not my 37778 UDP port. I've tried many different things but my phone app keeps giving me a cannot login error message. Any help is appreciated....just looking for a nudge in the right direction because i am totally stuck

thank you for the suggestions, so it turns out for some reason the DVR wasn't recognizing its own internal IP for some reason. I just changed the internal IP to something else and forwarded ports 81 and 37777, and it worked for some reason. Thank you for all the suggestions, I definitely spent alot of time researching the forums and has helped me alot. looking forward to posting more.!

thank you sir! I will be looking into all of those suggestions.