WHEN TRYING TO ENTER TAX ON IGST CUSTOMER ITS NOT ACCEPTING NOW BEFORE IT WAS OK?

Not worry, gireeshanak-dnse. We can work together to get this sorted out so you can get back to business.

You'll want to check if there are changes to the address. If there's none, then let's figure out if this has something to do with your browser's cache.

We can use a private browser to open your account and see if you can successfully enter the tax on IGST customer.

Please use these keyboard shortcuts:

• Google Chrome: press Ctrl + Shift + N
• Mozilla Firefox: press Ctrl + Shift + P
• Safari: press Command + Shift +N

If it works, let's go back to the regular browser and clear its cache. This eliminates excessive browsing history that may cause this glitch on your browser. Otherwise, you can use other supported browsers. 

I've added some links about adding GSTIN and applying IGST on invoices for your reference:

• How to add GSTIN for customers
• How do I apply IGST on my invoices?

Keep me posted on how the steps work. I want to make sure you're able to add the tax on your customer.