Hello,
(I know it is not a problem with kirby because it works very well with online website.)
I 've some troubles to work on local with links in tags. It redirects to the error page. I’ve Downloaded Blogprint to make some tests and problem is the same on local with tags and categories links. I never had any problems with kirby on local, it’s the first time and only with tags.
Thank you in advance if someone can help.
Not much help but I had the same issue a while ago:
In my menu I’ve: (this works on local but not online)
<a href="<?php echo url('collections/cat;' . urlencode($tag)) ?>">#<?php echo $tag; ?></a>
and if I use “:” instead of “;” it will work online but not on local
<a href="<?php echo url('collections/cat:' . urlencode($tag)) ?>">#<?php echo $tag; ?></a>
If it can helps to find why ?? 
In Kirby 2.2.x you can use url::paramSeparator() instead of “;” or “:”. This will give you the right separator depending on the environment.
You can also use:
<?php echo url('collections/' . url::paramsToString(['cat' => $tag])) ?>
which is especially useful if you have more than just one param.
Thank you Bastian. You saved my day