ModelBuilder not giving actual result

Question

I have 20 pairs of origin and destination. I also have 20 different line barriers for those pairs, as I want to determine the shortest path between them. If the name of the origin and destination is 100 then the name of the corresponding barrier is also 100. So, I build the model based upon the algorithm in previous study.

The model has an iterator that will select the pair of O-D and corresponding barrier one at a time, to find the shortest path between Origin and Destination. The problem is although there is a route between them, final output doesn't have shortest path for some O-D pairs. When I try to do it one by one, it works (i.e. shortest path for all of them is obtained easily). But, when I try to do it using ModelBuilder, only 6 out of 20 shortest path is obtained. The error I get is " No route from location 1 to location 2".

The main confusion is that the MODEL can solve the shortest path for 6 of them.(if there is problem it should have failed to solve any of them or if there was no any problem it should be able to solve all of them)

Can you help with this problem?

There is no any disconnectivity between the segments and no one way restrictions too.

I added some of the road segments with all of its snapping options activated but the route analysis fails to go through that node. Below is the snap of the Network Dataset. The highlighted segments are the newly added segments.

Answer 1

Initially the input files (for O-D and barriers) were saved in GDB, and they did not have the FID for each entry. Then when the input files were saved as shape files (not in any GDB), it got FID values. Then it started to give me correct results for all of them but I don't know what difference that made on adding the points and barrier for the route analysis.

Moral: Input for the route analysis should not be saved in GDB (at least in my case it happened)

For the final part: I used Feature to line tool to convert the road network (preserving the attributes). I built the network and then the problem was solved. The Question Splitting Roads at intersection for ArcGIS Network Analyst? have explanation on these.