Mobile inter-app "deep links" Not working using ZIP321 uri

[michaelharms6010]

I'm currently quite excited about deep links as a way to improve ZECpages mobile usability. I changed ZECpages's ZIP321 uri's to <a> links, but my phone doesn't like them.

Platform: iPhone 8
Apps: Brave and Safari
Both flash an error: "Cannot open page due to invalid address."
I have an up-to-date install of ZecWallet

I would love for clicking these links to open ZecWallet automatically.

My implementation (live now on zecpages) is:
<a href="zcash:uristring">zcash:uristring</a>
for every zip321 uri in ZP (for likes and posting)